diff --git a/src/ops.c b/src/ops.c
index d77aa2e..489c473 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -4635,7 +4635,7 @@
     {
 	/* Set the '] mark. */
 	curwin->w_buffer->b_op_end.lnum = curwin->w_cursor.lnum;
-	curwin->w_buffer->b_op_end.col  = (colnr_T)STRLEN(newp);
+	curwin->w_buffer->b_op_end.col  = (colnr_T)sumsize;
     }
 
     /* Only report the change in the first line here, del_lines() will report