diff --git a/include/functions.php b/include/functions.php
index 4272c649d..1ab92475d 100644
--- a/include/functions.php
+++ b/include/functions.php
@@ -872,7 +872,7 @@
 
 			$tz_offset = $user_tz->getOffset($dt);
 		} else {
-			$tz_offset = (int) $_SESSION["clientTzOffset"];
+			$tz_offset = (int) -$_SESSION["clientTzOffset"];
 		}
 
 		$user_timestamp = $dt->format('U') + $tz_offset;