diff --git a/window-copy.c b/window-copy.c
index 186f018d..5ab163cc 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -1055,6 +1055,8 @@ window_copy_write_line(
 	if (py == 0) {
 		size = xsnprintf(hdr, sizeof hdr,
 		    "[%u/%u]", data->oy, screen_hsize(data->backing));
+		if (size > screen_size_x(s))
+			size = screen_size_x(s);
 		screen_write_cursormove(ctx, screen_size_x(s) - size, 0);
 		screen_write_puts(ctx, &gc, "%s", hdr);
 	} else if (py == last && data->inputtype != WINDOW_COPY_OFF) {