Question 1

Will my online alarm work if my computer goes to sleep?

Accepted Answer

Interval uses the Web Notifications API and Web Audio API to trigger alarms. If your computer is asleep or the tab is fully suspended by the OS, the alarm audio may not play. For best results, keep your device awake — Interval includes a built-in Screen Wake Lock feature that prevents your screen from sleeping while alarms are active.

Question 2

Can I use Interval completely offline?

Accepted Answer

Yes. Interval is a Progressive Web App (PWA) with a service worker that caches all assets. Once you visit the app, the clock, alarms, timers, and stopwatch all work without any internet connection. You can also install it to your home screen or desktop for a native app experience.

Question 3

Is Interval really free with no ads?

Accepted Answer

Yes, Interval is 100% free and open-source with zero ads, zero tracking, and zero sign-up required. The full source code is available on GitHub.

Question 4

How accurate is the online stopwatch?

Accepted Answer

Interval's stopwatch uses requestAnimationFrame and performance.now() for sub-millisecond precision. It tracks both lap times and cumulative split times, with automatic fastest/slowest lap highlighting and CSV export.

Question 5

Can I set multiple alarms and timers at the same time?

Accepted Answer

Yes. You can create unlimited alarms with individual schedules, labels, and sound choices. The timer module supports multiple simultaneous countdown timers, and you can chain them into sequences for interval training like Pomodoro sessions.

Question 6

What is the Pomodoro timer and how do I use it?

Accepted Answer

The Pomodoro Technique uses 25-minute work intervals followed by 5-minute breaks. In Interval, tap the 'Pomodoro' preset to instantly start a 25-minute timer, or use the Sequence Builder to create a full session with automatic work-rest-repeat cycles.

Question 7

How do I compare times across different cities?

Accepted Answer

Add any city from 400+ worldwide timezones using the 'Add City' button. Interval shows live time, UTC offset, and the exact time difference between all your selected zones. Use the Meeting Planner slider to scrub forward or backward in time to coordinate across timezones.