diff --git a/src/Auth/User.php b/src/Auth/User.php
index 785420e..45ab149 100644
--- a/src/Auth/User.php
+++ b/src/Auth/User.php
@@ -71,6 +71,10 @@ public function __construct($data)
             }
         }
 
+        $sessionLifetime = !is_numeric($sessionLifetime)
+            ? strtotime($sessionLifetime)
+            : (time() + $sessionLifetime);
+
         $this->tokens['access'] = $this->generateToken($sessionLifetime);
         $this->tokens['refresh'] = $this->generateToken($sessionLifetime + 259200);
     }