diff --git a/gtk/gtkroundedbox.c b/gtk/gtkroundedbox.c
index 4aeffcde05..236997227b 100644
--- a/gtk/gtkroundedbox.c
+++ b/gtk/gtkroundedbox.c
@@ -171,7 +171,7 @@ _gtk_rounded_box_grow (GtkRoundedBox *box,
       box->box.width += left + right;
     }
 
-  if (box->box.height + bottom + right < 0)
+  if (box->box.height + bottom + top < 0)
     {
       box->box.y -= top * box->box.height / (top + bottom);
       box->box.height = 0;