diff --git a/layout/tables/nsTableRowGroupFrame.cpp b/layout/tables/nsTableRowGroupFrame.cpp
index ec337e0b751e..cf724cf583ca 100644
--- a/layout/tables/nsTableRowGroupFrame.cpp
+++ b/layout/tables/nsTableRowGroupFrame.cpp
@@ -520,7 +520,7 @@ nsTableRowGroupFrame::CalculateRowHeights(nsPresContext*          aPresContext,
 
   // all table cells have the same top and bottom margins, namely cellSpacingY
   nscoord cellSpacingY = tableFrame->GetCellSpacingY();
-  GET_TWIPS_TO_PIXELS(aPresContext, p2t);
+  GET_PIXELS_TO_TWIPS(aPresContext, p2t);
 
   PRInt32 numEffCols = tableFrame->GetEffectiveColCount();