diff --git a/src/mac/carbon/printmac.cpp b/src/mac/carbon/printmac.cpp
index bb1901b3eb..f601443a28 100644
--- a/src/mac/carbon/printmac.cpp
+++ b/src/mac/carbon/printmac.cpp
@@ -29,14 +29,12 @@
 #include "wx/msgdlg.h"
 #endif
 
+#include "wx/math.h"
 #include "wx/mac/uma.h"
 
 #include "wx/mac/printmac.h"
 #include "wx/mac/private/print.h"
 
-#define mm2pt            2.83464566929
-#define pt2mm            0.352777777778
-
 #include "wx/dcprint.h"
 #include "wx/printdlg.h"
 #include "wx/mac/printdlg.h"