Interval timer (Tabata / HIIT)
Configurable work, rest, rounds and sets with countdown and phase-change beeps: train without watching the clock.
Total: 05:45 · elapsed: 00:00
About this timer
- The timeline is computed from a clock timestamp, not accumulated intervals: it does not drift even if the tab throttles.
- A beep sounds in the last 3 seconds of each phase (countdown) and a double beep switches work to rest. Volume depends on the device.
- Rest can be 0 for continuous training, and sets with a long break allow multi-round circuits.
- Built for workouts, not for work: screen wake lock engages when you press start and releases on pause or completion.
- Fullscreen mode enlarges the ring so it is readable from across the room.
- If the tab closes, the timer stops: no email or mobile alerts.
Built by
Miguel Ángel Colorado Marin (MACM)
Built by
Miguel Ángel Colorado Marin (MACM)
Full-Stack Developer · Guadalajara, España
I develop web apps, digital tools and full projects — from design to deployment.
Training by intervals with a phone in hand is a battle against apps: mid-set ads, paywalled round limits, screens that sleep. This interval timer is pure and complete, and built for workouts, not for work: define work (5 s to 10 min), rest, rounds, sets and the long inter-set break, with presets covering 90% of workouts — Tabata 30/15 ×8, HIIT 60/30 ×4, circuit 40/20 ×6 ×2. The difference that matters: pressing start engages the browser's screen wake lock — the phone stays awake — and fullscreen mode enlarges the ring so it is readable from across the room. Beeps sound in the last 3 seconds of each phase (a low-tone countdown) and the work-to-rest switch is marked by a sharp double beep. Time is computed from a clock timestamp, so it does not drift even if the tab throttles. For productivity there is the Pomodoro; this is the gym timer.
Features
- ✓Ready presets: Tabata 30/15 ×8, HIIT 60/30 ×4 and circuit 40/20 ×6 ×2
- ✓Rounds (1-30) and sets (1-10) with configurable inter-set break
- ✓Screen wake lock: the phone stays awake while you train
- ✓Fullscreen mode so the ring is readable from across the room
- ✓3-second audible countdown and double beep on phase change
- ✓Drift-free timing, fully local in the browser
How do I use an interval timer?
- 1
Pick a preset or configure
Tabata, HIIT or circuit ready; or work, rest, rounds and sets by hand.
- 2
Press start
The ring shows total progress and each phase's countdown.
- 3
Train by ear
Three short beeps warn of the phase end; the sharp double beep sends you to rest.
- 4
Skip or reset
Skip a phase if your circuit changes, or reset everything to repeat the session.
Frequently asked questions
What is the Tabata protocol?
20 seconds of all-out work and 10 of rest, repeated 8 times (4 minutes). The included preset uses 30/15 ×8, the most common gym variant; you can set the original protocol's exact times by hand.
Does the screen turn off while I train?
No: pressing start engages the browser's screen wake lock while the timer runs, releasing on pause or completion. There is also a fullscreen mode with a large ring readable from across the room. That is the key difference from a work Pomodoro, where a sleeping screen is not a problem.
Can I do multi-set circuits?
Yes: set the rounds per set and the long inter-set break (10 s to 10 min). The timer chains everything and tells you which round and set you are on.
Does the screen sleep or lose time?
Time is computed from a clock timestamp, not accumulated intervals: even if the browser throttles the tab, the count does not drift. Keep the tab open though; there are no email or mobile alerts.
Related tools
Embed Interval Timer on your site
Add Interval Timer to any web page with a simple iframe. Free, with attribution to miguelacm.es.
<iframe
src="https://miguelacm.es/embed/interval-timer"
width="100%"
height="700"
frameborder="0"
title="Interval Timer — miguelacm.es"
></iframe>