diff --git a/Web/Models/Entities/User.php b/Web/Models/Entities/User.php
index e810bf0f..81d6cc08 100644
--- a/Web/Models/Entities/User.php
+++ b/Web/Models/Entities/User.php
@@ -324,7 +324,7 @@ class User extends RowModel
 
     function getAge(): ?int
     {
-        return (int)floor((time() - $this->getBirthday()->timestamp()) / mktime(0, 0, 0, 1, 1, 1971));
+        return (int)floor((time() - $this->getBirthday()->timestamp()) / YEAR);
     }
     
     function get2faSecret(): ?string
diff --git a/bootstrap.php b/bootstrap.php
index 1a52140c..c4ac5395 100644
--- a/bootstrap.php
+++ b/bootstrap.php
@@ -232,6 +232,14 @@ return (function() {
     else
         $ver = "Build 15";
 
+    // Unix time constants
+    define('MINUTE', 60);
+    define('HOUR', 60 * MINUTE);
+    define('DAY', 24 * HOUR);
+    define('WEEK', 7 * DAY);
+    define('MONTH', 30 * DAY);
+    define('YEAR', 365 * DAY);
+
     define("nullptr", NULL);
     define("OPENVK_DEFAULT_INSTANCE_NAME", "OpenVK", false);
     define("OPENVK_VERSION", "Altair Preview ($ver)", false);