diff --git a/src/memline.c b/src/memline.c
index d79e7ce..6b4a766 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -5380,7 +5380,7 @@
 	    // lengths.
 	    len = 0;
 	    for (i = start_idx; i <= idx; ++i)
-		len += STRLEN((char_u *)dp + ((dp->db_index[idx]) & DB_INDEX_MASK)) + 1;
+		len += STRLEN((char_u *)dp + ((dp->db_index[i]) & DB_INDEX_MASK)) + 1;
 	}
 	else
 #endif