How to Use CountdownTimerHQ

Complete guide to setting countdown timers, loop intervals, alarm tones, and fullscreen display mode.

Step-by-Step Instructions

  1. Select or Enter Time: Choose any preset duration or enter custom hours, minutes, and seconds.
  2. Press Start: Click the Start button. Fullscreen or loop mode can be enabled at any time.
  3. Background Tab Accuracy: Leave the tab running; our Web Worker ensures zero timer lag even when you switch tabs.

Frequently Asked Questions

How do I start a countdown timer?
Choose a timer duration from the homepage, then click the Start button. The timer begins counting down immediately and shows the remaining time in large digits.
Can I pause the timer?
Yes. Click the Pause button to freeze the timer at any time, then click Resume to continue from exactly where you paused — no time is lost.
How do I add more time during a countdown?
While the timer is running or paused, click the +1 min or +5 min buttons to add time without restarting. The countdown continues from the new total.
How does fullscreen mode work?
Click the Fullscreen button to expand the timer to fill your entire screen. This is useful for classroom activities, group workouts, and presentations.
Will the timer work if I switch to another tab?
Yes. A Web Worker keeps the countdown accurate even when the tab is in the background. The browser tab title also updates every second.