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Interval Timer

HIIT and Tabata work-rest loops with beeps.

Press F for fullscreen

work · round 1 / 8

45

About Interval Timer

An interval timer for HIIT, Tabata, and custom work-rest loops. Set a work duration, a rest duration, and the number of rounds. The timer beeps at every transition and displays the current round number. Built for gym sessions, circuit training, and any workout that alternates between effort and recovery.

Tabata and Beyond

Tabata is a specific interval protocol: 20 seconds of work, 10 seconds of rest, 8 rounds, for a total of 4 minutes. Research by Dr. Izumi Tabata showed this protocol improved both aerobic and anaerobic capacity more effectively than 60 minutes of steady-state cardio. The interval timer handles Tabata out of the box, but also supports any custom work/rest ratio — 40/20, 30/30, or asymmetric patterns like 45/15.

Audio Cues

A double-beep marks the work-to-rest transition. A triple-beep marks the rest-to-work transition. The final round ends with a longer tone. The audio cues are synthesized in the browser, so they fire instantly with no buffering — critical when a one-second delay means you are still resting when the work phase has already begun.

How to use it

  1. 01

    Set work and rest

    Edit the work duration, rest duration, and number of rounds before pressing Start.

  2. 02

    Press Start

    The first work phase begins. The round counter shows '1 of N'.

  3. 03

    Follow the beeps

    Double-beep = switch to rest. Triple-beep = switch back to work.

  4. 04

    Finish

    The final beep marks the end of the last round. Total elapsed time is displayed.

Frequently asked

The shortest path between you and the answer.

Can I do 20 rounds?

Yes. The round counter handles any number up to 99. For Tabata, set 8 rounds with 20s work / 10s rest.

Is this tool free?

Yes. Every ScreenTools.co tool is free, with no account, no paywall, and no install.

Does it work on mobile?

Yes. Layouts adapt to phone and tablet screens. Mobile Safari restricts true fullscreen, but the page fills the viewport and you can add the page to your Home Screen for an app-like experience.

Does it work offline?

Once a tool's page has loaded once, the runtime is local. A few tools that fetch fonts or icons need the first hit online; after that, refresh works offline.

Does this collect my data?

No personal data leaves your browser. The site has lightweight, privacy-respecting analytics for aggregate counts (which tool was opened) and nothing else.

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