diff --git a/gdk/gdkrgbaprivate.h b/gdk/gdkrgbaprivate.h
index fc355f5913..7701479bcc 100644
--- a/gdk/gdkrgbaprivate.h
+++ b/gdk/gdkrgbaprivate.h
@@ -33,7 +33,7 @@
     ((_GDK_RGBA_SELECT_COLOR(str, 0, 0) << 4) | _GDK_RGBA_SELECT_COLOR(str, 0, 1)) / 255., \
     ((_GDK_RGBA_SELECT_COLOR(str, 1, 2) << 4) | _GDK_RGBA_SELECT_COLOR(str, 1, 3)) / 255., \
     ((_GDK_RGBA_SELECT_COLOR(str, 2, 4) << 4) | _GDK_RGBA_SELECT_COLOR(str, 2, 5)) / 255., \
-    ((sizeof(str) % 4 == 1) ? ((_GDK_RGBA_SELECT_COLOR(str, 3, 6) << 4) | _GDK_RGBA_SELECT_COLOR(str, 3, 7)) : 0xFF) / 255 })
+    ((sizeof(str) % 4 == 1) ? ((_GDK_RGBA_SELECT_COLOR(str, 3, 6) << 4) | _GDK_RGBA_SELECT_COLOR(str, 3, 7)) : 0xFF) / 255. })
 
 
 gboolean               gdk_rgba_parser_parse                    (GtkCssParser           *parser,