diff --git a/app/scodoc/sco_permissions.py b/app/scodoc/sco_permissions.py
index 512caa8a5..ccf46e8e8 100644
--- a/app/scodoc/sco_permissions.py
+++ b/app/scodoc/sco_permissions.py
@@ -70,7 +70,8 @@ class Permission(object):
             setattr(Permission, symbol, perm)
             Permission.description[symbol] = description
             Permission.permission_by_name[symbol] = perm
-        Permission.NBITS = len(_SCO_PERMISSIONS)
+        max_perm = max(p[0] for p in _SCO_PERMISSIONS)
+        Permission.NBITS = max_perm.bit_length()
 
     @staticmethod
     def get_by_name(permission_name: str) -> int: