diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index 586ae11975..5a22f49ead 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -2239,6 +2239,9 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 #ifdef THREADED_DELTA_SEARCH
 	if (!delta_search_threads)	/* --threads=0 means autodetect */
 		delta_search_threads = online_cpus();
+	if (progress)
+		fprintf(stderr, "Using %d pack threads.\n",
+			delta_search_threads);
 #endif
 
 	prepare_packed_git();