diff --git a/Code/Mantid/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/CutMD.py b/Code/Mantid/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/CutMD.py
index deb86d1b8ca7..3136b8667140 100644
--- a/Code/Mantid/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/CutMD.py
+++ b/Code/Mantid/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/CutMD.py
@@ -111,7 +111,7 @@ def __calculate_extents(self, v, u, w, limits):
            for k in Krange:
                for l in Lrange:
                    original_corner=np.array([h,k,l])
-                   new_coords[counter]=original_corner.dot(Minv)
+                   new_coords[counter]=np.dot(original_corner, Minv)
                    counter += 1
         
         # Get the min max extents