diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 143ea55..b4351b2 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -177,7 +177,7 @@
 	if (width <= 0)
 	    width = curbuf->b_p_tw;
 	if (width == 0 && curbuf->b_p_wm > 0)
-	    width = W_WIDTH(curwin) - curbuf->b_p_wm;
+	    width = curwin->w_width - curbuf->b_p_wm;
 	if (width <= 0)
 	    width = 80;
     }