1 files changed, 3 insertions, 0 deletions

diff --git a/README.md b/README.md
index fb877f0..049c31d 100644
--- a/README.md
+++ b/README.md
@@ -227,3 +227,6 @@ The cube after the move F looks like this:
 ```
 MBODSFQH=ZBCYEFGHQTKL
 ```
+
+A cube in B32 format is always 21 characters long (22 if the terminating
+null character is included).