diff --git a/opm/core/grid/GridHelpers.cpp b/opm/core/grid/GridHelpers.cpp
index 2371aeff..40ac5b57 100644
--- a/opm/core/grid/GridHelpers.cpp
+++ b/opm/core/grid/GridHelpers.cpp
@@ -63,6 +63,12 @@ double faceArea(const UnstructuredGrid& grid, int face_index)
     return grid.face_areas[face_index];
 }
 
+int faceTag(const UnstructuredGrid& grid,
+            boost::iterator_range<const int*>::const_iterator face)
+{
+    return grid.cell_facetag[face-cell2Faces(grid)[0].begin()];
+}
+
 SparseTableView cell2Faces(const UnstructuredGrid& grid)
 {
     return SparseTableView(grid.cell_faces, grid.cell_facepos, numCells(grid));
diff --git a/opm/core/grid/GridHelpers.hpp b/opm/core/grid/GridHelpers.hpp
index cba87232..f7ff2c85 100644
--- a/opm/core/grid/GridHelpers.hpp
+++ b/opm/core/grid/GridHelpers.hpp
@@ -181,6 +181,12 @@ const double* faceNormal(const UnstructuredGrid& grid, int face_index);
 /// \param face_index The index of the face in the grid.
 double faceArea(const UnstructuredGrid& grid, int face_index);
 
+/// \brief Get Eclipse Cartesian tag of a face
+/// \param grid The grid that the face is part of.
+/// \param cell_face The face attached to a cell as obtained from cell2Faces()
+/// \return 0, 1, 2, 3, 4, 5 for I-, I+, J-, J+, K-, K+
+int faceTag(const UnstructuredGrid& grid, boost::iterator_range<const int*>::const_iterator cell_face);
+
 /// \brief Maps the grid type to the associated type of the cell to faces mapping.
 ///
 /// Provides a type named Type.