diff --git a/window-copy.c b/window-copy.c
index 9486265e..c2ce8837 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -1,4 +1,4 @@
-/* $Id: window-copy.c,v 1.57 2009-03-30 21:08:04 nicm Exp $ */
+/* $Id: window-copy.c,v 1.58 2009-03-31 12:28:45 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -487,7 +487,7 @@ window_copy_copy_line(struct window_pane *wp,
 				(*buf)[(*off)++] = gc->data;
 			} else {
 				gu = grid_peek_utf8(wp->base.grid, i, sy);
-				*buf = xrealloc(*buf, 1, (*off) + 8);
+				*buf = xrealloc(*buf, 1, (*off) + UTF8_SIZE);
 				for (j = 0; j < UTF8_SIZE; j++) {
 					if (gu->data[i] == 0xff)
 						break;