diff --git a/usr.sbin/freebsd-update/freebsd-update.8 b/usr.sbin/freebsd-update/freebsd-update.8
index 6741f422ca93..87f786a2c814 100644
--- a/usr.sbin/freebsd-update/freebsd-update.8
+++ b/usr.sbin/freebsd-update/freebsd-update.8
@@ -128,6 +128,11 @@ Fetch files necessary for upgrading to a new release.
 Before using this command, make sure that you read the
 announcement and release notes for the new release in
 case there are any special steps needed for upgrading.
+Note that this command may require up to 500 MB of space in
+.Ar workdir
+depending on which components of the
+.Fx
+base system are installed.
 .It Cm install
 Install the most recently fetched updates or upgrade.
 .It Cm rollback