diff --git a/library/Icinga/Util/Format.php b/library/Icinga/Util/Format.php
index f3e682128..79839b825 100644
--- a/library/Icinga/Util/Format.php
+++ b/library/Icinga/Util/Format.php
@@ -54,11 +54,13 @@ class Format
 
     public static function seconds($value)
     {
-        if ($value < 60) {
+        $absValue = abs($value);
+
+        if ($absValue < 60) {
             return self::formatForUnits($value, self::$secondPrefix, self::$secondBase);
-        } elseif ($value < 3600) {
+        } elseif ($absValue < 3600) {
             return sprintf('%0.2f m', $value / 60);
-        } elseif ($value < 86400) {
+        } elseif ($absValue < 86400) {
             return sprintf('%0.2f h', $value / 3600);
         }