diff --git a/opm/material/common/Spline.hpp b/opm/material/common/Spline.hpp
index 8b06ecd66..8816afad4 100644
--- a/opm/material/common/Spline.hpp
+++ b/opm/material/common/Spline.hpp
@@ -251,12 +251,6 @@ public:
            bool sortInputs = false)
     { this->setContainerOfPoints(points, m0, m1, sortInputs); }
 
-    /*!
-     * \brief Returns the number of sampling points.
-     */
-    size_t numSamples() const
-    { return xPos_.size(); }
-
     /*!
      * \brief Set the sampling points and the boundary slopes of the
      *        spline with two sampling points.
@@ -717,29 +711,24 @@ public:
         return x_(0) <= x && x <= x_(numSamples() - 1);
     }
 
-    /*!
-     * \brief Return the x value of the leftmost sampling point.
-     */
-    Scalar xMin() const
-    { return x_(0); }
 
     /*!
-     * \brief Return the x value of the rightmost sampling point.
+     * \brief Return the number of (x, y) values.
      */
-    Scalar xMax() const
-    { return x_(numSamples() - 1); }
+    size_t numSamples() const
+    { return xPos_.size(); }
 
     /*!
-     * \brief Return the y value of the leftmost sampling point.
+     * \brief Return the x value of a given sampling point.
      */
-    Scalar yFirst() const
-    { return y_(0); }
+    Scalar xAt(int sampleIdx) const
+    { return x_(sampleIdx); }
 
     /*!
-     * \brief Return the y value of the rightmost sampling point.
+     * \brief Return the x value of a given sampling point.
      */
-    Scalar yLast() const
-    { return y_(numSamples() - 1); }
+    Scalar valueAt(int sampleIdx) const
+    { return y_(sampleIdx); }
 
     /*!
      * \brief Prints k tuples of the format (x, y, dx/dy, isMonotonic)
@@ -812,15 +801,15 @@ public:
 
         // handle extrapolation
         if (extrapolate) {
-            if (x < xMin()) {
-                Scalar m = evalDerivative_(xMin(), /*segmentIdx=*/0);
+            if (x < xAt(0)) {
+                Scalar m = evalDerivative_(xAt(0), /*segmentIdx=*/0);
                 Scalar y0 = y_(0);
-                return y0 + m*(x - xMin());
+                return y0 + m*(x - xAt(0));
             }
-            else if (x > xMax()) {
-                Scalar m = evalDerivative_(xMax(), /*segmentIdx=*/numSamples()-2);
+            else if (x > xAt(numSamples() - 1)) {
+                Scalar m = evalDerivative_(xAt(numSamples() - 1), /*segmentIdx=*/numSamples()-2);
                 Scalar y0 = y_(numSamples() - 1);
-                return y0 + m*(x - xMax());
+                return y0 + m*(x - xAt(numSamples() - 1));
             }
         }
 
@@ -845,15 +834,15 @@ public:
 
         // handle extrapolation
         if (extrapolate) {
-            if (x.value < xMin()) {
-                Scalar m = evalDerivative_(xMin(), /*segmentIdx=*/0);
+            if (x.value < xAt(0)) {
+                Scalar m = evalDerivative_(xAt(0), /*segmentIdx=*/0);
                 Scalar y0 = y_(0);
-                return Evaluation::createConstant(y0 + m*(x.value - xMin()));
+                return Evaluation::createConstant(y0 + m*(x.value - xAt(0)));
             }
-            else if (x > xMax()) {
-                Scalar m = evalDerivative_(xMax(), /*segmentIdx=*/numSamples()-2);
+            else if (x > xAt(numSamples() - 1)) {
+                Scalar m = evalDerivative_(xAt(numSamples() - 1), /*segmentIdx=*/numSamples()-2);
                 Scalar y0 = y_(numSamples() - 1);
-                return Evaluation::createConstant(y0 + m*(x.value - xMax()));
+                return Evaluation::createConstant(y0 + m*(x.value - xAt(numSamples() - 1)));
             }
         }
 
@@ -876,10 +865,10 @@ public:
     {
         assert(extrapolate || applies(x));
         if (extrapolate) {
-            if (x < xMin())
-                return evalDerivative_(xMin(), /*segmentIdx=*/0);
-            else if (x > xMax())
-                return evalDerivative_(xMax(), /*segmentIdx=*/numSamples() - 2);
+            if (x < xAt(0))
+                return evalDerivative_(xAt(0), /*segmentIdx=*/0);
+            else if (x > xAt(numSamples() - 1))
+                return evalDerivative_(xAt(numSamples() - 1), /*segmentIdx=*/numSamples() - 2);
         }
 
         return evalDerivative_(x, segmentIdx_(x));
@@ -939,7 +928,7 @@ public:
                          const Evaluation& c,
                          const Evaluation& d) const
     {
-        return intersectInterval(xMin(), xMax(), a, b, c, d);
+        return intersectInterval(xAt(0), xAt(numSamples() - 1), a, b, c, d);
     }
 
     /*!
@@ -1000,12 +989,12 @@ public:
         assert(x0 < x1);
 
         int r = 3;
-        if (x0 < xMin()) {
+        if (x0 < xAt(0)) {
             assert(extrapolate);
-            Scalar m = evalDerivative_(xMin(), /*segmentIdx=*/0);
+            Scalar m = evalDerivative_(xAt(0), /*segmentIdx=*/0);
             if (std::abs(m) < 1e-20)
                 r = (m < 0)?-1:1;
-            x0 = xMin();
+            x0 = xAt(0);
         };
 
         size_t i = segmentIdx_(x0);
@@ -1033,10 +1022,10 @@ public:
         // if the user asked for a part of the spline which is
         // extrapolated, we need to check the slope at the spline's
         // endpoint
-        if (x1 > xMax()) {
+        if (x1 > xAt(numSamples() - 1)) {
             assert(extrapolate);
 
-            Scalar m = evalDerivative_(xMax(), /*segmentIdx=*/numSamples() - 2);
+            Scalar m = evalDerivative_(xAt(numSamples() - 1), /*segmentIdx=*/numSamples() - 2);
             if (m < 0)
                 return (r < 0 || r==3)?-1:0;
             else if (m > 0)
@@ -1056,7 +1045,7 @@ public:
      *        spline as interval.
      */
     int monotonic() const
-    { return monotonic(xMin(), xMax()); }
+    { return monotonic(xAt(0), xAt(numSamples() - 1)); }
 
 protected:
     /*!
diff --git a/opm/material/fluidmatrixinteractions/SplineTwoPhaseMaterial.hpp b/opm/material/fluidmatrixinteractions/SplineTwoPhaseMaterial.hpp
index bb1af9575..5ecd5020b 100644
--- a/opm/material/fluidmatrixinteractions/SplineTwoPhaseMaterial.hpp
+++ b/opm/material/fluidmatrixinteractions/SplineTwoPhaseMaterial.hpp
@@ -139,12 +139,13 @@ public:
     static Evaluation twoPhaseSatPcnw(const Params &params, const Evaluation& Sw)
     {
         // this assumes that the capillary pressure is monotonically decreasing
-        if (Sw <= params.pcnwSpline().xMin())
-            return Evaluation(params.pcnwSpline().yFirst());
-        if (Sw >= params.pcnwSpline().xMax())
-            return Evaluation(params.pcnwSpline().yLast());
+        const auto& pcnwSpline = params.pcnwSpline();
+        if (Sw <= pcnwSpline.xAt(0))
+            return Evaluation(pcnwSpline.valueAt(0));
+        if (Sw >= pcnwSpline.xAt(pcnwSpline.numSamples() - 1))
+            return Evaluation(pcnwSpline.valueAt(pcnwSpline.numSamples() - 1));
 
-        return params.pcnwSpline().eval(Sw);
+        return pcnwSpline.eval(Sw);
     }
 
     template <class Evaluation>
@@ -153,14 +154,15 @@ public:
         static const Evaluation nil(0.0);
 
         // this assumes that the capillary pressure is monotonically decreasing
-        if (pcnw >= params.pcnwSpline().yFirst())
-            return Evaluation(params.pcnwSpline().xMin());
-        if (pcnw <= params.pcnwSpline().yLast())
-            return Evaluation(params.pcnwSpline().xMax());
+        const auto& pcnwSpline = params.pcnwSpline();
+        if (pcnw >= pcnwSpline.valueAt(0))
+            return Evaluation(pcnwSpline.xAt(0));
+        if (pcnw <= pcnwSpline.y(pcnwSpline.numSamples() - 1))
+            return Evaluation(pcnwSpline.xAt(pcnwSpline.numSamples() - 1));
 
         // the intersect() method of splines is a bit slow, but this code path is not too
         // time critical...
-        return params.pcnwSpline().intersect(/*a=*/nil, /*b=*/nil, /*c=*/nil, /*d=*/pcnw);
+        return pcnwSpline.intersect(/*a=*/nil, /*b=*/nil, /*c=*/nil, /*d=*/pcnw);
     }
 
     /*!
@@ -204,12 +206,13 @@ public:
     template <class Evaluation>
     static Evaluation twoPhaseSatKrw(const Params &params, const Evaluation& Sw)
     {
-        if (Sw <= params.krnSpline().xMin())
-            return Evaluation(params.krwSpline().yFirst());
-        if (Sw >= params.krnSpline().xMax())
-            return Evaluation(params.krwSpline().yLast());
+        const auto& krwSpline = params.krwSpline();
+        if (Sw <= krwSpline.xAt(0))
+            return Evaluation(krwSpline.valueAt(0));
+        if (Sw >= krwSpline.xAt(krwSpline.numSamples() - 1))
+            return Evaluation(krwSpline.valueAt(krwSpline.numSamples() - 1));
 
-        return params.krwSpline().eval(Sw);
+        return krwSpline.eval(Sw);
     }
 
     template <class Evaluation>
@@ -217,12 +220,13 @@ public:
     {
         static const Evaluation nil(0.0);
 
-        if (krw <= params.krwSpline().yFirst())
-            return Evaluation(params.krwSpline().xMin());
-        if (krw >= params.krwSpline().yLast())
-            return Evaluation(params.krwSpline().xMax());
+        const auto& krwSpline = params.krwSpline();
+        if (krw <= krwSpline.valueAt(0))
+            return Evaluation(krwSpline.xAt(0));
+        if (krw >= krwSpline.valueAt(krwSpline.numSamples() - 1))
+            return Evaluation(krwSpline.xAt(krwSpline.numSamples() - 1));
 
-        return params.krwSpline().intersect(/*a=*/nil, /*b=*/nil, /*c=*/nil, /*d=*/krw);
+        return krwSpline.intersect(/*a=*/nil, /*b=*/nil, /*c=*/nil, /*d=*/krw);
     }
 
     /*!
@@ -243,12 +247,13 @@ public:
     template <class Evaluation>
     static Evaluation twoPhaseSatKrn(const Params &params, const Evaluation& Sw)
     {
-        if (Sw <= params.krnSpline().xMin())
-            return Evaluation(params.krnSpline().yFirst());
-        if (Sw >= params.krnSpline().xMax())
-            return Evaluation(params.krnSpline().yLast());
+        const auto& krnSpline = params.krnSpline();
+        if (Sw <= krnSpline.xAt(0))
+            return Evaluation(krnSpline.valueAt(0));
+        if (Sw >= krnSpline.xAt(krnSpline.numSamples() - 1))
+            return Evaluation(krnSpline.valueAt(krnSpline.numSamples() - 1));
 
-        return params.krnSpline().eval(Sw);
+        return krnSpline.eval(Sw);
     }
 
     template <class Evaluation>
@@ -256,12 +261,13 @@ public:
     {
         static const Evaluation nil(0.0);
 
-        if (krn >= params.krnSpline().yFirst())
-            return Evaluation(params.krnSpline().xMin());
-        if (krn <= params.krnSpline().yLast())
-            return Evaluation(params.krnSpline().xMax());
+        const auto& krnSpline = params.krnSpline();
+        if (krn >= krnSpline.valueAt(0))
+            return Evaluation(krnSpline.xAt(0));
+        if (krn <= krnSpline.valueAt(krnSpline.numSamples() - 1))
+            return Evaluation(krnSpline.xAt(krnSpline.numSamples() - 1));
 
-        return params.krnSpline().intersect(/*a=*/nil, /*b=*/nil, /*c=*/nil, /*d=*/krn);
+        return krnSpline.intersect(/*a=*/nil, /*b=*/nil, /*c=*/nil, /*d=*/krn);
     }
 };
 } // namespace Opm
diff --git a/tests/test_spline.cpp b/tests/test_spline.cpp
index 2aa24a15c..c9b11625b 100644
--- a/tests/test_spline.cpp
+++ b/tests/test_spline.cpp
@@ -82,7 +82,9 @@ void testCommon(const Spline &sp,
     // make sure the derivatives are consistent with the curve
     size_t np = 3*n;
     for (size_t i = 0; i < np; ++i) {
-        double xval = sp.xMin() + (sp.xMax() - sp.xMin())*i/np;
+        double xMin = sp.xAt(0);
+        double xMax = sp.xAt(sp.numSamples() - 1);
+        double xval = xMin + (xMax - xMin)*i/np;
 
         // first derivative
         double y1 = sp.eval(xval+epsFD);