diff --git a/object-name.c b/object-name.c
index 523af6f64f..1be2ad1a16 100644
--- a/object-name.c
+++ b/object-name.c
@@ -837,7 +837,7 @@ int repo_find_unique_abbrev_r(struct repository *r, char *hex,
 	}
 
 	oid_to_hex_r(hex, oid);
-	if (len == hexsz || !len)
+	if (len >= hexsz || !len)
 		return hexsz;
 
 	mad.repo = r;