diff --git a/srv/poe_manager/templates/index.html b/srv/poe_manager/templates/index.html
index b3e19c3..4a1735a 100644
--- a/srv/poe_manager/templates/index.html
+++ b/srv/poe_manager/templates/index.html
@@ -46,8 +46,8 @@ document.addEventListener("DOMContentLoaded", () => {
     function updateTimer() {
         const now = Date.now();
         const elapsed = now - lastUpdateTime;
-        const remainingMs = intervalMilliseconds - elapsed;
-        const remainingSec = Math.ceil(Math.max(remainingMs, 0) / 1000);
+        const remainingMs = intervalMilliseconds - (elapsed % intervalMilliseconds);
+        const remainingSec = Math.ceil(remainingMs / 1000);
         document.getElementById("dashboard-timer").innerText =
             `Nächste Prüfung in ${remainingSec} Sekunden`;