diff --git a/README.md b/README.md
index ebd60d9..ff037de 100644
--- a/README.md
+++ b/README.md
@@ -81,7 +81,7 @@ Storage Overhead
 
 * Empty files take 0 bytes on disk
 * 18 byte file header for non-empty files (2 bytes version, 16 bytes random file id)
-* 28 bytes of storage overhead per 4kB block (12 byte nonce, 16 bytes auth tag)
+* 32 bytes of storage overhead per 4kB block (16 byte nonce, 16 bytes auth tag)
 
 [file-format.md](Documentation/file-format.md) contains a more detailed description.