diff --git a/app/widgets/gimptoolpalette.c b/app/widgets/gimptoolpalette.c
index d459266c59..e411305d95 100644
--- a/app/widgets/gimptoolpalette.c
+++ b/app/widgets/gimptoolpalette.c
@@ -256,7 +256,10 @@ gimp_tool_palette_height_for_width (GtkWidget *widget,
                                            &button_width, &button_height,
                                            &min_columns, &min_rows);
 
-  tool_columns = MAX (min_columns, width / button_width);
+  if (button_width != 0)
+    tool_columns = MAX (min_columns, width / button_width);
+  else
+    tool_columns = min_columns;
   tool_rows    = n_tools / tool_columns;
 
   if (n_tools % tool_columns)