diff --git a/opm/material/fluidsystems/BlackOilFluidSystem.hpp b/opm/material/fluidsystems/BlackOilFluidSystem.hpp
index 903eb610c..9d1f1c4ca 100644
--- a/opm/material/fluidsystems/BlackOilFluidSystem.hpp
+++ b/opm/material/fluidsystems/BlackOilFluidSystem.hpp
@@ -380,39 +380,39 @@ public:
         case oilPhaseIdx: {
             if (!enableDissolvedGas()) {
                 // immiscible oil
-                const auto& Bo = formationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
-                return referenceDensity(phaseIdx, regionIdx)/Bo;
+                const auto& bo = inverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
+                return referenceDensity(phaseIdx, regionIdx)*bo;
             }
 
             // miscible oil
-            const auto& Bo = formationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
+            const auto& bo = inverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
             const auto& Rs = getRs_<LhsEval, FluidState>(fluidState, regionIdx);
 
             return
-                referenceDensity(oilPhaseIdx, regionIdx)/Bo
-                + Rs*referenceDensity(gasPhaseIdx, regionIdx)/Bo;
+                bo*referenceDensity(oilPhaseIdx, regionIdx)
+                + Rs*bo*referenceDensity(gasPhaseIdx, regionIdx);
         }
 
         case gasPhaseIdx: {
             if (!enableVaporizedOil()) {
                 // immiscible gas
-                const auto& Bg = formationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
-                return Bg*referenceDensity(phaseIdx, regionIdx);
+                const auto& bg = inverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
+                return bg*referenceDensity(phaseIdx, regionIdx);
             }
 
             // miscible gas
-            const auto& Bg = formationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
+            const auto& bg = inverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
             const auto& Rv = getRv_<LhsEval, FluidState>(fluidState, regionIdx);
 
             return
-                referenceDensity(gasPhaseIdx, regionIdx)/Bg
-                + Rv*referenceDensity(oilPhaseIdx, regionIdx)/Bg;
+                bg*referenceDensity(gasPhaseIdx, regionIdx)
+                + Rv*bg*referenceDensity(oilPhaseIdx, regionIdx);
         }
 
         case waterPhaseIdx:
             return
                 referenceDensity(waterPhaseIdx, regionIdx)
-                /formationVolumeFactor<FluidState, LhsEval>(fluidState, waterPhaseIdx, regionIdx);
+                *inverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, waterPhaseIdx, regionIdx);
         }
 
         OPM_THROW(std::logic_error, "Unhandled phase index " << phaseIdx);
@@ -437,39 +437,39 @@ public:
         case oilPhaseIdx: {
             if (!enableDissolvedGas()) {
                 // immiscible oil
-                const auto& Bo = formationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
-                return referenceDensity(phaseIdx, regionIdx)/Bo;
+                const auto& bo = inverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
+                return referenceDensity(phaseIdx, regionIdx)*bo;
             }
 
             // miscible oil
-            const auto& Bo = saturatedFormationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
+            const auto& bo = saturatedInverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
             const auto& Rs = saturatedDissolutionFactor<FluidState, LhsEval>(fluidState, oilPhaseIdx, regionIdx);
 
             return
-                referenceDensity(oilPhaseIdx, regionIdx)/Bo
-                + Rs*referenceDensity(gasPhaseIdx, regionIdx)/Bo;
+                bo*referenceDensity(oilPhaseIdx, regionIdx)
+                + Rs*bo*referenceDensity(gasPhaseIdx, regionIdx);
         }
 
         case gasPhaseIdx: {
             if (!enableVaporizedOil()) {
                 // immiscible gas
-                const auto& Bg = formationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
-                return referenceDensity(phaseIdx, regionIdx)/Bg;
+                const auto& bg = inverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
+                return referenceDensity(phaseIdx, regionIdx)*bg;
             }
 
             // miscible gas
-            const auto& Bg = saturatedFormationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
+            const auto& bg = saturatedInverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
             const auto& Rv = saturatedDissolutionFactor<FluidState, LhsEval>(fluidState, gasPhaseIdx, regionIdx);
 
             return
-                referenceDensity(gasPhaseIdx, regionIdx)/Bg
-                + Rv*referenceDensity(oilPhaseIdx, regionIdx)/Bg;
+                bg*referenceDensity(gasPhaseIdx, regionIdx)
+                + Rv*bg*referenceDensity(oilPhaseIdx, regionIdx);
         }
 
         case waterPhaseIdx:
             return
                 referenceDensity(waterPhaseIdx, regionIdx)
-                /saturatedFormationVolumeFactor<FluidState, LhsEval>(fluidState, waterPhaseIdx, regionIdx);
+                *saturatedInverseFormationVolumeFactor<FluidState, LhsEval>(fluidState, waterPhaseIdx, regionIdx);
         }
 
         OPM_THROW(std::logic_error, "Unhandled phase index " << phaseIdx);
@@ -484,9 +484,9 @@ public:
      * the given temperature and pressure.
      */
     template <class FluidState, class LhsEval = typename FluidState::Scalar>
-    static LhsEval formationVolumeFactor(const FluidState& fluidState,
-                                         unsigned phaseIdx,
-                                         unsigned regionIdx)
+    static LhsEval inverseFormationVolumeFactor(const FluidState& fluidState,
+                                                unsigned phaseIdx,
+                                                unsigned regionIdx)
     {
         assert(0 <= phaseIdx && phaseIdx <= numPhases);
         assert(0 <= regionIdx && regionIdx <= numRegions());
@@ -497,12 +497,56 @@ public:
         const auto& T = FsToolbox::template toLhs<LhsEval>(fluidState.temperature(phaseIdx));
 
         switch (phaseIdx) {
-        case oilPhaseIdx:
-            return oilPvt_->formationVolumeFactor(regionIdx, T, p, getRs_<LhsEval>(fluidState, regionIdx));
-        case gasPhaseIdx:
-            return gasPvt_->formationVolumeFactor(regionIdx, T, p, getRv_<LhsEval>(fluidState, regionIdx));
+        case oilPhaseIdx: {
+            if (enableDissolvedGas()) {
+                if (fluidState.saturation(gasPhaseIdx) > 0.0) {
+                    if (fluidState.saturation(gasPhaseIdx) < 1e-4) {
+                        // here comes the relatively expensive case: first calculate and then
+                        // interpolate between the saturated and undersaturated quantities to
+                        // avoid a discontinuity
+                        const auto& Rs = getRs_<LhsEval, FluidState>(fluidState, regionIdx);
+                        const auto& alpha = FsToolbox::template toLhs<LhsEval>(fluidState.saturation(gasPhaseIdx))/1e-4;
+                        const auto& bSat = oilPvt_->saturatedInverseFormationVolumeFactor(regionIdx, T, p);
+                        const auto& bUndersat = oilPvt_->inverseFormationVolumeFactor(regionIdx, T, p, Rs);
+                        return alpha*bSat + (1.0 - alpha)*bUndersat;
+                    }
+
+                    return oilPvt_->saturatedInverseFormationVolumeFactor(regionIdx, T, p);
+                }
+
+                const auto& Rs = getRs_<LhsEval, FluidState>(fluidState, regionIdx);
+                return oilPvt_->inverseFormationVolumeFactor(regionIdx, T, p, Rs);
+            }
+
+            const LhsEval Rs(0.0);
+            return oilPvt_->inverseFormationVolumeFactor(regionIdx, T, p, Rs);
+        }
+        case gasPhaseIdx: {
+            if (enableVaporizedOil()) {
+                if (fluidState.saturation(oilPhaseIdx) > 0.0) {
+                    if (fluidState.saturation(oilPhaseIdx) < 1e-4) {
+                        // here comes the relatively expensive case: first calculate and then
+                        // interpolate between the saturated and undersaturated quantities to
+                        // avoid a discontinuity
+                        const auto& Rv = getRv_<LhsEval, FluidState>(fluidState, regionIdx);
+                        const auto& alpha = FsToolbox::template toLhs<LhsEval>(fluidState.saturation(oilPhaseIdx))/1e-4;
+                        const auto& bSat = gasPvt_->saturatedInverseFormationVolumeFactor(regionIdx, T, p);
+                        const auto& bUndersat = gasPvt_->inverseFormationVolumeFactor(regionIdx, T, p, Rv);
+                        return alpha*bSat + (1.0 - alpha)*bUndersat;
+                    }
+
+                    return gasPvt_->saturatedInverseFormationVolumeFactor(regionIdx, T, p);
+                }
+
+                const auto& Rv = getRv_<LhsEval, FluidState>(fluidState, regionIdx);
+                return gasPvt_->inverseFormationVolumeFactor(regionIdx, T, p, Rv);
+            }
+
+            const LhsEval Rv(0.0);
+            return gasPvt_->inverseFormationVolumeFactor(regionIdx, T, p, Rv);
+        }
         case waterPhaseIdx:
-            return waterPvt_->formationVolumeFactor(regionIdx, T, p);
+            return waterPvt_->inverseFormationVolumeFactor(regionIdx, T, p);
         default: OPM_THROW(std::logic_error, "Unhandled phase index " << phaseIdx);
         }
     }
@@ -515,9 +559,9 @@ public:
      * saturated and for the water phase, there is no difference to formationVolumeFactor()
      */
     template <class FluidState, class LhsEval = typename FluidState::Scalar>
-    static LhsEval saturatedFormationVolumeFactor(const FluidState& fluidState,
-                                                  unsigned phaseIdx,
-                                                  unsigned regionIdx)
+    static LhsEval saturatedInverseFormationVolumeFactor(const FluidState& fluidState,
+                                                         unsigned phaseIdx,
+                                                         unsigned regionIdx)
     {
         assert(0 <= phaseIdx && phaseIdx <= numPhases);
         assert(0 <= regionIdx && regionIdx <= numRegions());
@@ -528,9 +572,9 @@ public:
         const auto& T = FsToolbox::template toLhs<LhsEval>(fluidState.temperature(phaseIdx));
 
         switch (phaseIdx) {
-        case oilPhaseIdx: return oilPvt_->saturatedFormationVolumeFactor(regionIdx, T, p);
-        case gasPhaseIdx: return gasPvt_->saturatedFormationVolumeFactor(regionIdx, T, p);
-        case waterPhaseIdx: return waterPvt_->formationVolumeFactor(regionIdx, T, p);
+        case oilPhaseIdx: return oilPvt_->saturatedInverseFormationVolumeFactor(regionIdx, T, p);
+        case gasPhaseIdx: return gasPvt_->saturatedInverseFormationVolumeFactor(regionIdx, T, p);
+        case waterPhaseIdx: return waterPvt_->inverseFormationVolumeFactor(regionIdx, T, p);
         default: OPM_THROW(std::logic_error, "Unhandled phase index " << phaseIdx);
         }
     }
@@ -678,56 +722,56 @@ public:
         const auto& T = FsToolbox::template toLhs<LhsEval>(fluidState.temperature(phaseIdx));
 
         switch (phaseIdx) {
-        case oilPhaseIdx:
-            if (!enableDissolvedGas())
-                // if the oil phase is immiscible with the gas component, we can use the
-                // "saturated" properties from the outset...
-                return oilPvt_->saturatedViscosity(regionIdx, T, p);
-            else if (fluidState.saturation(gasPhaseIdx) > 0.0) {
-                if (fluidState.saturation(gasPhaseIdx) < 1e-4) {
-                    // here comes the relatively expensive case: first calculate and then
-                    // interpolate between the saturated and undersaturated quantities to
-                    // avoid a discontinuity
-                    const auto& Rs = getRs_<LhsEval>(fluidState, regionIdx);
-                    const auto& alpha = FsToolbox::template toLhs<LhsEval>(fluidState.saturation(gasPhaseIdx))/1e-4;
-                    const auto& muSat = oilPvt_->saturatedViscosity(regionIdx, T, p);
-                    const auto& muUndersat = oilPvt_->viscosity(regionIdx, T, p, Rs);
-                    return alpha*muSat + (1.0 - alpha)*muUndersat;
+        case oilPhaseIdx: {
+            if (enableDissolvedGas()) {
+                if (fluidState.saturation(gasPhaseIdx) > 0.0) {
+                    if (fluidState.saturation(gasPhaseIdx) < 1e-4) {
+                        // here comes the relatively expensive case: first calculate and then
+                        // interpolate between the saturated and undersaturated quantities to
+                        // avoid a discontinuity
+                        const auto& Rs = getRs_<LhsEval, FluidState>(fluidState, regionIdx);
+                        const auto& alpha = FsToolbox::template toLhs<LhsEval>(fluidState.saturation(gasPhaseIdx))/1e-4;
+                        const auto& muSat = oilPvt_->saturatedViscosity(regionIdx, T, p);
+                        const auto& muUndersat = oilPvt_->viscosity(regionIdx, T, p, Rs);
+                        return alpha*muSat + (1.0 - alpha)*muUndersat;
+                    }
+
+                    return oilPvt_->saturatedViscosity(regionIdx, T, p);
                 }
 
-                return oilPvt_->saturatedViscosity(regionIdx, T, p);
-            }
-            else {
-                // undersaturated oil
-                const auto& Rs = getRs_<LhsEval>(fluidState, regionIdx);
+                const auto& Rs = getRs_<LhsEval, FluidState>(fluidState, regionIdx);
                 return oilPvt_->viscosity(regionIdx, T, p, Rs);
             }
 
-        case gasPhaseIdx:
-            if (!enableVaporizedOil())
-                // if the gas phase is immiscible with the oil component, we can use the
-                // saturated properties from the outset...
-                return gasPvt_->saturatedViscosity(regionIdx, T, p);
-            else if (fluidState.saturation(oilPhaseIdx) > 0.0) {
-                if (fluidState.saturation(oilPhaseIdx) < 1e-4) {
-                    // here comes the relatively expensive case: first calculate and then
-                    // interpolate between the saturated and undersaturated quantities to
-                    // avoid a discontinuity
-                    const auto& Rv = getRv_<LhsEval>(fluidState, regionIdx);
-                    const auto& alpha = FsToolbox::template toLhs<LhsEval>(fluidState.saturation(oilPhaseIdx))/1e-4;
-                    const auto& muSat = gasPvt_->saturatedViscosity(regionIdx, T, p);
-                    const auto& muUndersat = gasPvt_->viscosity(regionIdx, T, p, Rv);
-                    return alpha*muSat + (1.0 - alpha)*muUndersat;
+            const LhsEval Rs(0.0);
+            return oilPvt_->viscosity(regionIdx, T, p, Rs);
+        }
+
+        case gasPhaseIdx: {
+            if (enableVaporizedOil()) {
+                if (fluidState.saturation(oilPhaseIdx) > 0.0) {
+                    if (fluidState.saturation(oilPhaseIdx) < 1e-4) {
+                        // here comes the relatively expensive case: first calculate and then
+                        // interpolate between the saturated and undersaturated quantities to
+                        // avoid a discontinuity
+                        const auto& Rv = getRv_<LhsEval, FluidState>(fluidState, regionIdx);
+                        const auto& alpha = FsToolbox::template toLhs<LhsEval>(fluidState.saturation(oilPhaseIdx))/1e-4;
+                        const auto& muSat = gasPvt_->saturatedViscosity(regionIdx, T, p);
+                        const auto& muUndersat = gasPvt_->viscosity(regionIdx, T, p, Rv);
+                        return alpha*muSat + (1.0 - alpha)*muUndersat;
+                    }
+
+                    return gasPvt_->saturatedViscosity(regionIdx, T, p);
                 }
 
-                return gasPvt_->saturatedViscosity(regionIdx, T, p);
-            }
-            else {
-                // undersaturated gas
-                const auto& Rv = getRv_<LhsEval>(fluidState, regionIdx);
+                const auto& Rv = getRv_<LhsEval, FluidState>(fluidState, regionIdx);
                 return gasPvt_->viscosity(regionIdx, T, p, Rv);
             }
 
+            const LhsEval Rv(0.0);
+            return gasPvt_->viscosity(regionIdx, T, p, Rv);
+        }
+
         case waterPhaseIdx:
             // since water is always assumed to be immiscible in the black-oil model,
             // there is no "saturated water"
diff --git a/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityOilPvt.hpp b/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityOilPvt.hpp
index b04d33def..a352775e3 100644
--- a/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityOilPvt.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityOilPvt.hpp
@@ -184,24 +184,24 @@ public:
         // calcultes the product of B_w and mu_w and then divides the
         // result by B_w...
         Scalar BoMuoRef = oilViscosity_[regionIdx]*oilReferenceFormationVolumeFactor_[regionIdx];
-        const Evaluation& Bo = saturatedFormationVolumeFactor(regionIdx, temperature, pressure);
+        const Evaluation& bo = saturatedInverseFormationVolumeFactor(regionIdx, temperature, pressure);
 
         Scalar pRef = oilReferencePressure_[regionIdx];
         const Evaluation& Y =
             (oilCompressibility_[regionIdx] - oilViscosibility_[regionIdx])
             * (pressure - pRef);
-        return BoMuoRef/((1 + Y*(1 + Y/2))*Bo);
+        return BoMuoRef*bo/(1.0 + Y*(1.0 + Y/2.0));
     }
 
     /*!
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& temperature,
-                                     const Evaluation& pressure,
-                                     const Evaluation& /*Rs*/) const
-    { return saturatedFormationVolumeFactor(regionIdx, temperature, pressure); }
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& temperature,
+                                            const Evaluation& pressure,
+                                            const Evaluation& /*Rs*/) const
+    { return saturatedInverseFormationVolumeFactor(regionIdx, temperature, pressure); }
 
     /*!
      * \brief Returns the formation volume factor [-] of gas saturated oil.
@@ -210,16 +210,16 @@ public:
      * is always gas saturated by by definition.
      */
     template <class Evaluation>
-    Evaluation saturatedFormationVolumeFactor(unsigned regionIdx,
-                                              const Evaluation& /*temperature*/,
-                                              const Evaluation& pressure) const
+    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
+                                                     const Evaluation& /*temperature*/,
+                                                     const Evaluation& pressure) const
     {
         // cf. ECLiPSE 2011 technical description, p. 116
         Scalar pRef = oilReferencePressure_[regionIdx];
         const Evaluation& X = oilCompressibility_[regionIdx]*(pressure - pRef);
 
         Scalar BoRef = oilReferenceFormationVolumeFactor_[regionIdx];
-        return BoRef/(1 + X*(1 + X/2));
+        return (1 + X*(1 + X/2))/BoRef;
     }
 
     /*!
diff --git a/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityWaterPvt.hpp b/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityWaterPvt.hpp
index 404b1fe19..68b08a75b 100644
--- a/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityWaterPvt.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/ConstantCompressibilityWaterPvt.hpp
@@ -181,9 +181,9 @@ public:
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& /*temperature*/,
-                                     const Evaluation& pressure) const
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& /*temperature*/,
+                                            const Evaluation& pressure) const
     {
         // cf. ECLiPSE 2011 technical description, p. 116
         Scalar pRef = waterReferencePressure_[regionIdx];
@@ -192,7 +192,7 @@ public:
         Scalar BwRef = waterReferenceFormationVolumeFactor_[regionIdx];
 
         // TODO (?): consider the salt concentration of the brine
-        return BwRef/(1 + X*(1 + X/2));
+        return (1.0 + X*(1.0 + X/2.0))/BwRef;
     }
 
 private:
diff --git a/opm/material/fluidsystems/blackoilpvt/DeadOilPvt.hpp b/opm/material/fluidsystems/blackoilpvt/DeadOilPvt.hpp
index 30eab7f28..30d8d0da9 100644
--- a/opm/material/fluidsystems/blackoilpvt/DeadOilPvt.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/DeadOilPvt.hpp
@@ -191,11 +191,11 @@ public:
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& /*temperature*/,
-                                     const Evaluation& pressure,
-                                     const Evaluation& /*Rs*/) const
-    { return 1.0 / inverseOilB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& /*temperature*/,
+                                            const Evaluation& pressure,
+                                            const Evaluation& /*Rs*/) const
+    { return inverseOilB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
 
     /*!
      * \brief Returns the formation volume factor [-] of saturated oil.
@@ -203,10 +203,10 @@ public:
      * Note that by definition, dead oil is always gas saturated.
      */
     template <class Evaluation>
-    Evaluation saturatedFormationVolumeFactor(unsigned regionIdx,
+    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
                                               const Evaluation& /*temperature*/,
                                               const Evaluation& pressure) const
-    { return 1.0 / inverseOilB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
+    { return inverseOilB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
 
     /*!
      * \brief Returns the gas dissolution factor \f$R_s\f$ [m^3/m^3] of the oil phase.
diff --git a/opm/material/fluidsystems/blackoilpvt/DryGasPvt.hpp b/opm/material/fluidsystems/blackoilpvt/DryGasPvt.hpp
index 41ca5cf4e..964450abe 100644
--- a/opm/material/fluidsystems/blackoilpvt/DryGasPvt.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/DryGasPvt.hpp
@@ -213,47 +213,24 @@ public:
         return invBg/invMugBg;
     }
 
-    /*!
-     * \brief Returns the density [kg/m^3] of the fluid phase given a set of parameters.
-     */
-    template <class Evaluation>
-    Evaluation density(unsigned regionIdx,
-                       const Evaluation& temperature,
-                       const Evaluation& pressure,
-                       const Evaluation& /*Rv*/) const
-    { return saturatedDensity(regionIdx, temperature, pressure); }
-
-    /*!
-     * \brief Returns the density [kg/m^3] of oil saturated gas at given pressure.
-     */
-    template <class Evaluation>
-    Evaluation saturatedDensity(unsigned regionIdx,
-                                const Evaluation& temperature,
-                                const Evaluation& pressure) const
-    {
-        // gas formation volume factor at reservoir pressure
-        const Evaluation& Bg = saturatedFormationVolumeFactor(regionIdx, temperature, pressure);
-        return gasReferenceDensity_[regionIdx]/Bg;
-    }
-
     /*!
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& temperature,
-                                     const Evaluation& pressure,
-                                     const Evaluation& /*Rv*/) const
-    { return saturatedFormationVolumeFactor(regionIdx, temperature, pressure); }
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& temperature,
+                                            const Evaluation& pressure,
+                                            const Evaluation& /*Rv*/) const
+    { return saturatedInverseFormationVolumeFactor(regionIdx, temperature, pressure); }
 
     /*!
      * \brief Returns the formation volume factor [-] of oil saturated gas at given pressure.
      */
     template <class Evaluation>
-    Evaluation saturatedFormationVolumeFactor(unsigned regionIdx,
-                                              const Evaluation& /*temperature*/,
-                                              const Evaluation& pressure) const
-    { return 1.0/inverseGasB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
+    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
+                                                     const Evaluation& /*temperature*/,
+                                                     const Evaluation& pressure) const
+    { return inverseGasB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
 
     /*!
      * \brief Returns the saturation pressure of the gas phase [Pa]
diff --git a/opm/material/fluidsystems/blackoilpvt/GasPvtMultiplexer.hpp b/opm/material/fluidsystems/blackoilpvt/GasPvtMultiplexer.hpp
index 8802e5bc2..f6c4c89c2 100644
--- a/opm/material/fluidsystems/blackoilpvt/GasPvtMultiplexer.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/GasPvtMultiplexer.hpp
@@ -162,20 +162,20 @@ public:
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation = Scalar>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& temperature,
-                                     const Evaluation& pressure,
-                                     const Evaluation& Rv) const
-    { OPM_GAS_PVT_MULTIPLEXER_CALL(return pvtImpl.formationVolumeFactor(regionIdx, temperature, pressure, Rv)); return 0; }
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& temperature,
+                                            const Evaluation& pressure,
+                                            const Evaluation& Rv) const
+    { OPM_GAS_PVT_MULTIPLEXER_CALL(return pvtImpl.inverseFormationVolumeFactor(regionIdx, temperature, pressure, Rv)); return 0; }
 
     /*!
      * \brief Returns the formation volume factor [-] of oil saturated gas given a set of parameters.
      */
     template <class Evaluation = Scalar>
-    Evaluation saturatedFormationVolumeFactor(unsigned regionIdx,
-                                              const Evaluation& temperature,
-                                              const Evaluation& pressure) const
-    { OPM_GAS_PVT_MULTIPLEXER_CALL(return pvtImpl.saturatedFormationVolumeFactor(regionIdx, temperature, pressure)); return 0; }
+    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
+                                                     const Evaluation& temperature,
+                                                     const Evaluation& pressure) const
+    { OPM_GAS_PVT_MULTIPLEXER_CALL(return pvtImpl.saturatedInverseFormationVolumeFactor(regionIdx, temperature, pressure)); return 0; }
 
     /*!
      * \brief Returns the oil vaporization factor \f$R_v\f$ [m^3/m^3] of oil saturated gas.
diff --git a/opm/material/fluidsystems/blackoilpvt/LiveOilPvt.hpp b/opm/material/fluidsystems/blackoilpvt/LiveOilPvt.hpp
index 3ea680bba..ad4935a3e 100644
--- a/opm/material/fluidsystems/blackoilpvt/LiveOilPvt.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/LiveOilPvt.hpp
@@ -433,25 +433,25 @@ public:
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& /*temperature*/,
-                                     const Evaluation& pressure,
-                                     const Evaluation& Rs) const
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& /*temperature*/,
+                                            const Evaluation& pressure,
+                                            const Evaluation& Rs) const
     {
         // ATTENTION: Rs is represented by the _first_ axis!
-        return 1.0 / inverseOilBTable_[regionIdx].eval(Rs, pressure, /*extrapolate=*/true);
+        return inverseOilBTable_[regionIdx].eval(Rs, pressure, /*extrapolate=*/true);
     }
 
     /*!
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation saturatedFormationVolumeFactor(unsigned regionIdx,
-                                              const Evaluation& /*temperature*/,
-                                              const Evaluation& pressure) const
+    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
+                                                     const Evaluation& /*temperature*/,
+                                                     const Evaluation& pressure) const
     {
         // ATTENTION: Rs is represented by the _first_ axis!
-        return 1.0 / inverseSaturatedOilBTable_[regionIdx].eval(pressure, /*extrapolate=*/true);
+        return inverseSaturatedOilBTable_[regionIdx].eval(pressure, /*extrapolate=*/true);
     }
 
     /*!
diff --git a/opm/material/fluidsystems/blackoilpvt/OilPvtMultiplexer.hpp b/opm/material/fluidsystems/blackoilpvt/OilPvtMultiplexer.hpp
index 3ad68f795..e000059c9 100644
--- a/opm/material/fluidsystems/blackoilpvt/OilPvtMultiplexer.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/OilPvtMultiplexer.hpp
@@ -153,20 +153,20 @@ public:
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& temperature,
-                                     const Evaluation& pressure,
-                                     const Evaluation& Rs) const
-    { OPM_OIL_PVT_MULTIPLEXER_CALL(return pvtImpl.formationVolumeFactor(regionIdx, temperature, pressure, Rs)); return 0; }
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& temperature,
+                                            const Evaluation& pressure,
+                                            const Evaluation& Rs) const
+    { OPM_OIL_PVT_MULTIPLEXER_CALL(return pvtImpl.inverseFormationVolumeFactor(regionIdx, temperature, pressure, Rs)); return 0; }
 
     /*!
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation saturatedFormationVolumeFactor(unsigned regionIdx,
-                                              const Evaluation& temperature,
-                                              const Evaluation& pressure) const
-    { OPM_OIL_PVT_MULTIPLEXER_CALL(return pvtImpl.saturatedFormationVolumeFactor(regionIdx, temperature, pressure)); return 0; }
+    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
+                                                     const Evaluation& temperature,
+                                                     const Evaluation& pressure) const
+    { OPM_OIL_PVT_MULTIPLEXER_CALL(return pvtImpl.saturatedInverseFormationVolumeFactor(regionIdx, temperature, pressure)); return 0; }
 
     /*!
      * \brief Returns the gas dissolution factor \f$R_s\f$ [m^3/m^3] of saturated oil.
diff --git a/opm/material/fluidsystems/blackoilpvt/WaterPvtMultiplexer.hpp b/opm/material/fluidsystems/blackoilpvt/WaterPvtMultiplexer.hpp
index 09bbdef2b..257a0407c 100644
--- a/opm/material/fluidsystems/blackoilpvt/WaterPvtMultiplexer.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/WaterPvtMultiplexer.hpp
@@ -107,10 +107,10 @@ public:
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& temperature,
-                                     const Evaluation& pressure) const
-    { OPM_WATER_PVT_MULTIPLEXER_CALL(return pvtImpl.formationVolumeFactor(regionIdx, temperature, pressure)); return 0; }
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& temperature,
+                                            const Evaluation& pressure) const
+    { OPM_WATER_PVT_MULTIPLEXER_CALL(return pvtImpl.inverseFormationVolumeFactor(regionIdx, temperature, pressure)); return 0; }
 
     void setApproach(WaterPvtApproach appr)
     {
diff --git a/opm/material/fluidsystems/blackoilpvt/WetGasPvt.hpp b/opm/material/fluidsystems/blackoilpvt/WetGasPvt.hpp
index 537e2334f..91436fcf5 100644
--- a/opm/material/fluidsystems/blackoilpvt/WetGasPvt.hpp
+++ b/opm/material/fluidsystems/blackoilpvt/WetGasPvt.hpp
@@ -464,20 +464,20 @@ public:
      * \brief Returns the formation volume factor [-] of the fluid phase.
      */
     template <class Evaluation>
-    Evaluation formationVolumeFactor(unsigned regionIdx,
-                                     const Evaluation& /*temperature*/,
-                                     const Evaluation& pressure,
-                                     const Evaluation& Rv) const
-    { return 1.0 / inverseGasB_[regionIdx].eval(pressure, Rv, /*extrapolate=*/true); }
+    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
+                                            const Evaluation& /*temperature*/,
+                                            const Evaluation& pressure,
+                                            const Evaluation& Rv) const
+    { return inverseGasB_[regionIdx].eval(pressure, Rv, /*extrapolate=*/true); }
 
     /*!
      * \brief Returns the formation volume factor [-] of oil saturated gas at a given pressure.
      */
     template <class Evaluation>
-    Evaluation saturatedFormationVolumeFactor(unsigned regionIdx,
-                                              const Evaluation& /*temperature*/,
-                                              const Evaluation& pressure) const
-    { return 1.0 / inverseSaturatedGasB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
+    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
+                                                     const Evaluation& /*temperature*/,
+                                                     const Evaluation& pressure) const
+    { return inverseSaturatedGasB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
 
     /*!
      * \brief Returns the gas dissolution factor \f$R_s\f$ [m^3/m^3] of the oil phase.
diff --git a/tests/test_eclblackoilpvt.cpp b/tests/test_eclblackoilpvt.cpp
index 9a3fbceed..98485d2a7 100644
--- a/tests/test_eclblackoilpvt.cpp
+++ b/tests/test_eclblackoilpvt.cpp
@@ -145,9 +145,9 @@ void ensurePvtApi(const OilPvt& oilPvt, const GasPvt& gasPvt, const WaterPvt& wa
         tmp = waterPvt.viscosity(/*regionIdx=*/0,
                                  temperature,
                                  pressure);
-        tmp = waterPvt.formationVolumeFactor(/*regionIdx=*/0,
-                                             temperature,
-                                             pressure);
+        tmp = waterPvt.inverseFormationVolumeFactor(/*regionIdx=*/0,
+                                                    temperature,
+                                                    pressure);
 
         /////
         // oil PVT API
@@ -156,16 +156,16 @@ void ensurePvtApi(const OilPvt& oilPvt, const GasPvt& gasPvt, const WaterPvt& wa
                                temperature,
                                pressure,
                                Rs);
-        tmp = oilPvt.formationVolumeFactor(/*regionIdx=*/0,
-                                           temperature,
-                                           pressure,
-                                           Rs);
+        tmp = oilPvt.inverseFormationVolumeFactor(/*regionIdx=*/0,
+                                                  temperature,
+                                                  pressure,
+                                                  Rs);
         tmp = oilPvt.saturatedViscosity(/*regionIdx=*/0,
                                         temperature,
                                         pressure);
-        tmp = oilPvt.saturatedFormationVolumeFactor(/*regionIdx=*/0,
-                                                    temperature,
-                                                    pressure);
+        tmp = oilPvt.saturatedInverseFormationVolumeFactor(/*regionIdx=*/0,
+                                                           temperature,
+                                                           pressure);
         tmp = oilPvt.saturationPressure(/*regionIdx=*/0,
                                         temperature,
                                         Rs);
@@ -180,16 +180,16 @@ void ensurePvtApi(const OilPvt& oilPvt, const GasPvt& gasPvt, const WaterPvt& wa
                                temperature,
                                pressure,
                                Rv);
-        tmp = gasPvt.formationVolumeFactor(/*regionIdx=*/0,
-                                           temperature,
-                                           pressure,
-                                           Rv);
+        tmp = gasPvt.inverseFormationVolumeFactor(/*regionIdx=*/0,
+                                                  temperature,
+                                                  pressure,
+                                                  Rv);
         tmp = gasPvt.saturatedViscosity(/*regionIdx=*/0,
                                         temperature,
                                         pressure);
-        tmp = gasPvt.saturatedFormationVolumeFactor(/*regionIdx=*/0,
-                                                    temperature,
-                                                    pressure);
+        tmp = gasPvt.saturatedInverseFormationVolumeFactor(/*regionIdx=*/0,
+                                                           temperature,
+                                                           pressure);
         tmp = gasPvt.saturationPressure(/*regionIdx=*/0,
                                         temperature,
                                         Rv);
diff --git a/tests/test_fluidsystems.cpp b/tests/test_fluidsystems.cpp
index ae512907b..f56bcd1a3 100644
--- a/tests/test_fluidsystems.cpp
+++ b/tests/test_fluidsystems.cpp
@@ -146,8 +146,8 @@ void ensureBlackoilApi()
         for (unsigned phaseIdx = 0; phaseIdx < FluidSystem::numPhases; ++ phaseIdx) {
             dummy = FluidSystem::density(fluidState, phaseIdx, /*regionIdx=*/0);
             dummy = FluidSystem::saturatedDensity(fluidState, phaseIdx, /*regionIdx=*/0);
-            dummy = FluidSystem::formationVolumeFactor(fluidState, phaseIdx, /*regionIdx=*/0);
-            dummy = FluidSystem::saturatedFormationVolumeFactor(fluidState, phaseIdx, /*regionIdx=*/0);
+            dummy = FluidSystem::inverseFormationVolumeFactor(fluidState, phaseIdx, /*regionIdx=*/0);
+            dummy = FluidSystem::saturatedInverseFormationVolumeFactor(fluidState, phaseIdx, /*regionIdx=*/0);
             dummy = FluidSystem::viscosity(fluidState, phaseIdx, /*regionIdx=*/0);
             dummy = FluidSystem::saturatedDissolutionFactor(fluidState, phaseIdx, /*regionIdx=*/0);
             dummy = FluidSystem::saturationPressure(fluidState, phaseIdx, /*regionIdx=*/0);