diff --git a/usr.sbin/makefs/ffs.c b/usr.sbin/makefs/ffs.c
index 1647d8f2268f..dd97c012dcea 100644
--- a/usr.sbin/makefs/ffs.c
+++ b/usr.sbin/makefs/ffs.c
@@ -418,6 +418,10 @@ ffs_validate(const char *dir, fsnode *root, fsinfo_t *fsopts)
 		/* round up to the next block */
 	fsopts->size = roundup(fsopts->size, ffs_opts->bsize);
 
+		/* round up to requested block size, if any */
+	if (fsopts->roundup > 0)
+		fsopts->size = roundup(fsopts->size, fsopts->roundup);
+
 		/* calculate density if necessary */
 	if (ffs_opts->density == -1)
 		ffs_opts->density = fsopts->size / fsopts->inodes + 1;
diff --git a/usr.sbin/makefs/makefs.8 b/usr.sbin/makefs/makefs.8
index 91ab2048718d..025066d293f6 100644
--- a/usr.sbin/makefs/makefs.8
+++ b/usr.sbin/makefs/makefs.8
@@ -53,6 +53,7 @@
 .Op Fl m Ar maximum-size
 .Op Fl N Ar userdb-dir
 .Op Fl o Ar fs-options
+.Op Fl r Ar roundup
 .Op Fl S Ar sector-size
 .Op Fl s Ar image-size
 .Op Fl t Ar fs-type
@@ -195,6 +196,9 @@ Deprecated.
 See the
 .Fl Z
 flag.
+.It Fl r Ar roundup
+Round the image up to specified block size that should be multiple
+of block size.
 .It Fl S Ar sector-size
 Set the file system sector size to
 .Ar sector-size .
diff --git a/usr.sbin/makefs/makefs.c b/usr.sbin/makefs/makefs.c
index bf10034f00d1..5e419ccb0d89 100644
--- a/usr.sbin/makefs/makefs.c
+++ b/usr.sbin/makefs/makefs.c
@@ -113,7 +113,7 @@ main(int argc, char *argv[])
 	start_time.tv_sec = start.tv_sec;
 	start_time.tv_nsec = start.tv_usec * 1000;
 
-	while ((ch = getopt(argc, argv, "B:b:Dd:f:F:M:m:N:o:ps:S:t:xZ")) != -1) {
+	while ((ch = getopt(argc, argv, "B:b:Dd:f:F:M:m:N:o:pr:s:S:t:xZ")) != -1) {
 		switch (ch) {
 
 		case 'B':
@@ -209,6 +209,12 @@ main(int argc, char *argv[])
 			fsoptions.sparse = 1;
 			break;
 
+		case 'r':
+			/* Round image size up to specified block size */
+			fsoptions.roundup =
+			    strsuftoll("roundup", optarg, 0, LLONG_MAX);
+			break;
+
 		case 's':
 			fsoptions.minsize = fsoptions.maxsize =
 			    strsuftoll("size", optarg, 1LL, LLONG_MAX);
@@ -359,9 +365,9 @@ usage(void)
 	prog = getprogname();
 	fprintf(stderr,
 "usage: %s [-t fs-type] [-o fs-options] [-d debug-mask] [-B endian]\n"
-"\t[-S sector-size] [-M minimum-size] [-m maximum-size] [-s image-size]\n"
-"\t[-b free-blocks] [-f free-files] [-F mtree-specfile] [-xZ]\n"
-"\t[-N userdb-dir] image-file directory | manifest [extra-directory ...]\n",
+"\t[-S sector-size] [-M minimum-size] [-m maximum-size] [-r roundup ]\n"
+"\t[-s image-size] [-b free-blocks] [-f free-files] [-F mtree-specfile]\n"
+"\t[-xZ] [-N userdb-dir] image-file directory | manifest [extra-directory ...]\n",
 	    prog);
 	exit(1);
 }
diff --git a/usr.sbin/makefs/makefs.h b/usr.sbin/makefs/makefs.h
index 5ab04446c687..ba80f74519a4 100644
--- a/usr.sbin/makefs/makefs.h
+++ b/usr.sbin/makefs/makefs.h
@@ -130,6 +130,7 @@ typedef struct {
 	int	needswap;	/* non-zero if byte swapping needed */
 	int	sectorsize;	/* sector size */
 	int	sparse;		/* sparse image, don't fill it with zeros */
+	off_t	roundup;	/* round image size up to this value */
 
 	void	*fs_specific;	/* File system specific additions. */
 } fsinfo_t;