diff --git a/config/speedtest.php b/config/speedtest.php
index 263729a5f..230afc091 100644
--- a/config/speedtest.php
+++ b/config/speedtest.php
@@ -16,7 +16,7 @@
 
     'public_dashboard' => env('PUBLIC_DASHBOARD', false),
 
-    'default_chart_range' => env('DEFAULT_CHART_RANGE', '24h'),
+    'default_chart_range' => strtolower(env('DEFAULT_CHART_RANGE', '24h')),
 
     /**
      * Speedtest settings.