diff --git a/sbin/newfs/mkfs.c b/sbin/newfs/mkfs.c
index 062a82d66c5b..89f86f577631 100644
--- a/sbin/newfs/mkfs.c
+++ b/sbin/newfs/mkfs.c
@@ -627,6 +627,7 @@ mkfs(pp, fsys, fi, fo)
 		if (cylno % 9 == 0)
 			printf("\n");
 		printf(" %d,", fsbtodb(&sblock, cgsblock(&sblock, cylno)));
+		fflush(stdout);
 	}
 	if (!mfs)
 		printf("\n");