diff --git a/auth.c b/auth.c
index 774e16a..1db2683 100644
--- a/auth.c
+++ b/auth.c
@@ -422,7 +422,7 @@ int auth_quota(const struct auth *const a, const char *const user,
             *available = true;
             *quota = strtoull(qs, &end, 10);
 
-            const unsigned long long mul = 1024 * 1024;
+            const unsigned long long mul = 1024ul * 1024ul;
 
             if (errno || *end != '\0')
             {
@@ -436,7 +436,7 @@ int auth_quota(const struct auth *const a, const char *const user,
                 goto end;
             }
 
-            *quota *= 1024 * 1024;
+            *quota *= mul;
             break;
         }
     }