diff --git a/app/helpers/datetime.php b/app/helpers/datetime.php
new file mode 100644
index 0000000..1511d30
--- /dev/null
+++ b/app/helpers/datetime.php
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * Datetime helper utilities.
+ *
+ * Centralized formatting for UTC timestamps into a specified timezone.
+ */
+
+if (!function_exists('app_format_local_datetime')) {
+    function app_format_local_datetime(?string $value, string $format, string $timezone): string
+    {
+        if (empty($value) || $value === '0000-00-00 00:00:00') {
+            return '';
+        }
+        try {
+            $utc = new DateTimeZone('UTC');
+            $tz = new DateTimeZone($timezone ?: 'UTC');
+            $date = new DateTimeImmutable($value, $utc);
+            return $date->setTimezone($tz)->format($format);
+        } catch (Throwable $e) {
+            return '';
+        }
+    }
+}