diff --git a/src/Mod/Part/App/TopoShape.cpp b/src/Mod/Part/App/TopoShape.cpp
index 8a2003cf1..01ba36afe 100644
--- a/src/Mod/Part/App/TopoShape.cpp
+++ b/src/Mod/Part/App/TopoShape.cpp
@@ -998,7 +998,7 @@ unsigned int TopoShape::getMemSize (void) const
                         break;
                     case GeomAbs_BezierSurface:
                         memsize += sizeof(Geom_BezierSurface);
-                        memsize += (surface.NbUPoles()+surface.NbUPoles()) * sizeof(Standard_Real);
+                        memsize += (surface.NbUPoles()*surface.NbVPoles()) * sizeof(Standard_Real);
                         memsize += (surface.NbUPoles()*surface.NbVPoles()) * sizeof(Geom_CartesianPoint);
                         break;
                     case GeomAbs_BSplineSurface: