diff --git a/sbin/fsck_ffs/inode.c b/sbin/fsck_ffs/inode.c
index 18a015f8187e24..60019425c825e7 100644
--- a/sbin/fsck_ffs/inode.c
+++ b/sbin/fsck_ffs/inode.c
@@ -611,8 +611,9 @@ setinodebuf(int cg, ino_t inosused)
 	    sizeof(struct ufs1_dinode) : sizeof(struct ufs2_dinode));
 	readpercg = inosused / fullcnt;
 	partialcnt = inosused % fullcnt;
-	partialsize = partialcnt * ((sblock.fs_magic == FS_UFS1_MAGIC) ?
-	    sizeof(struct ufs1_dinode) : sizeof(struct ufs2_dinode));
+	partialsize = fragroundup(&sblock,
+	    partialcnt * ((sblock.fs_magic == FS_UFS1_MAGIC) ?
+	    sizeof(struct ufs1_dinode) : sizeof(struct ufs2_dinode)));
 	if (partialcnt != 0) {
 		readpercg++;
 	} else {