Need a work/rest timer for HIIT, Tabata, boxing rounds or any other timed training — without downloading an app or fumbling with a stopwatch mid-set? This free online interval timer counts down each round for you, cues every phase change with sound, and keeps timing accurately even if you lock your phone or switch tabs. Pick a built-in preset or set your own work, rest and round count, and get moving.
What is an interval timer?
An interval timer is a tool that alternates automatically between a work period and a rest period, repeating for a set number of rounds, and tells you when each one ends without you having to watch it. Instead of glancing at a stopwatch and restarting it by hand every 20 or 30 seconds, you set the pattern once and the timer cycles through it, cueing every change with sound.
It's the engine behind named training formats like Tabata and HIIT, behind boxing and combat-sports round timers, and behind any other routine built from repeating work/rest blocks — including non-fitness ones like the Pomodoro technique for focused study or work sprints.
How to use this interval timer
It takes a few seconds to set up, and there's nothing to install:
- Pick a preset or set your own. Tap Tabata, HIIT, Boxing round, EMOM or Pomodoro to load their times instantly, or leave it on Custom and enter your own work, rest and rounds.
- Add a warm-up or cooldown if you want one. Flip the Add warm-up or Add cooldown switch and a duration field appears for each.
- Check the total time. The Total hint below Rounds recalculates live as you change any field, so you know the full length before you start.
- Hit Start. The setup screen is replaced by the run view — a countdown ring, the current phase and round, and round-by-round dots.
- Skip, pause or reset mid-run. Skip jumps to the next phase, Pause/Resume holds the clock, and Reset ends the run completely and takes you back to setup.
Built-in presets: Tabata, HIIT, boxing, EMOM and Pomodoro
Six options sit above the setup fields — five real presets plus Custom. Picking one instantly fills in every field to match; editing any field afterward switches the selector back to Custom on its own, so you always know whether you're looking at a preset or your own numbers.
| Preset | Work | Rest | Rounds | Warm-up | Cooldown | Total time |
|---|---|---|---|---|---|---|
| Tabata | 0:20 | 0:10 | 8 | Off | Off | 3:50 |
| HIIT | 0:30 | 0:15 | 8 | 0:30 (on) | 1:00 (on) | 7:15 |
| Boxing round | 3:00 | 1:00 | 12 | Off | Off | 47:00 |
| EMOM | 1:00 | 0:00 | 10 | Off | Off | 10:00 |
| Pomodoro | 25:00 | 5:00 | 4 | Off | Off | 1:55:00 |
Note that HIIT is the only preset with warm-up and cooldown switched on by default — the other four start with both off, though you can add either to any of them.
Custom work, rest, warm-up and cooldown
Every duration field — Work, Rest, Warm-up time and Cooldown time — accepts either M:SS (like 1:30) or a plain number of seconds (like 90), which is normalized back into M:SS as soon as you leave the field. Each also has small − and + stepper buttons that adjust it by 5 seconds at a time, and Rounds has its own stepper that adjusts by 1.
Work has to be more than 0 seconds and Rounds has to be at least 1, but Rest can be set to 0 — that's intentional, not a bug, since some formats like EMOM run rounds back-to-back with no rest between them. Work and Rest can each go up to 180 minutes, Warm-up and Cooldown up to 60 minutes each, and Rounds up to 99.
The run screen: countdown ring, round dots and sound cues
Once you hit Start, a circular countdown ring drains around the time remaining in the current phase, changing color depending on what phase you're in — blue for Work, red for Rest, and a muted gray for Warm-up or Cooldown. Underneath, a row of round dots fills in as you progress, so you can see at a glance how many rounds are done and how many are left.
Every phase change plays a short tone, and the final three seconds of each phase get their own countdown beep so you know a change is coming without watching the screen. The mute button at the top turns all sound off if you'd rather train in silence. Three controls sit below the ring: Skip jumps straight to the next phase, Pause/Resume holds and restarts the clock exactly where it left off, and Reset ends the run entirely and takes you back to the setup screen — it isn't a soft reset that zeroes the current round and keeps going.
Keeps time accurately in the background
The countdown is calculated from the actual clock every time the screen updates, rather than by ticking a number down once a second — so it stays exactly accurate even after your browser throttles a backgrounded tab, which is a common way simpler timers drift. The browser tab's title also updates with the live countdown and phase, so you can check your time from another tab without switching back. Where your browser supports it, the timer requests a screen wake lock while running so your phone or laptop doesn't lock mid-round, and re-requests it automatically if the tab regains focus during a run.
What can you use an interval timer for?
Anywhere you need repeating, cued work and rest periods instead of watching a stopwatch yourself:
- HIIT workouts — high-intensity intervals with a set work and rest split, with the HIIT preset's built-in warm-up and cooldown
- Tabata training — the classic 20-seconds-on, 10-seconds-off format, ready to go with the Tabata preset
- Boxing and combat-sports rounds — the Boxing round preset's 3-minute rounds with a 1-minute break, or your own round length
- Circuit training — a station-by-station workout using Custom work/rest times and however many rounds you need
- EMOM strength sessions — one continuous work block per round with the EMOM preset's zero-rest setup
- Study or focus sprints — the Pomodoro preset's 25-minute work / 5-minute break cycle for timed, distraction-free work sessions
- Cooking and kitchen tasks — timing repeating steps (simmer, stir, rest) back-to-back with Custom durations instead of resetting a single kitchen timer each time
Interval timer vs. a gym clock or your phone's stopwatch
A wall-mounted gym interval clock is fixed to one room and whatever program it's set to that day — fine if you're already there, useless anywhere else. Your phone's built-in stopwatch or single-countdown timer app does one clock at a time: it can count down a work period, but then you have to notice it ended, restart it for rest, notice that ends, and restart it again — every single round. This tool sets the whole pattern once — work, rest, rounds, warm-up and cooldown — and cycles through it on its own, with a distinct sound cue for every phase change, for free in any browser on any device.
Your timer settings stay on your device
Your work/rest/round configuration, your last-used preset and your mute choice are all saved automatically in your browser's local storage, and your theme preference is saved separately — both are restored the next time you open the page so you don't have to re-enter your setup. Nothing about your timer, your workout or your session is sent to a server; it all stays on your own device.
Frequently asked questions
Is there a free online interval timer?
Yes — this page is one. Open it on any phone or computer, set your work and rest times (or pick a preset), and start. No download, account or payment is needed.
What is an interval timer?
An interval timer alternates between work and rest periods for a set number of rounds, cueing every phase change with sound and a visual countdown so you don't have to watch a stopwatch yourself. It's the timing engine behind HIIT, Tabata, boxing rounds and similar work/rest training.
What presets does this interval timer include?
Six: Tabata (20s work / 10s rest / 8 rounds), HIIT (30s work / 15s rest / 8 rounds with a 30s warm-up and 60s cooldown), Boxing round (3 min work / 1 min rest / 12 rounds), EMOM (60s work per round, no rest, 10 rounds), Pomodoro (25 min work / 5 min rest / 4 rounds), and Custom for any combination of your own.
Can I set my own work, rest and round times?
Yes. Choose Custom, or edit any field on a preset (which switches the selector to Custom automatically), and set work and rest as M:SS or a plain number of seconds, plus rounds, warm-up and cooldown.
Does the timer keep working if I switch tabs or my screen locks?
Yes. The countdown is calculated from the clock rather than ticked down one second at a time, so it stays accurate even after a backgrounded tab. Where your browser supports it, the timer also requests a screen wake lock while running, and the browser tab's title updates with the live countdown so you can see it without switching back.
Can I use this on my iPhone or Android instead of a separate timer app?
Yes. It runs in your phone's browser with sound cues and a screen wake lock, so you don't need to install a dedicated interval timer app — just open the page and start.
Is there a limit to how long I can set work, rest, warm-up or cooldown?
Work and rest can each go up to 180 minutes, warm-up and cooldown up to 60 minutes each, and rounds up to 99 — comfortably past what any real workout or study session would need.
Is my timer setup saved if I close the browser?
Yes. Your work/rest/round settings, your last-used preset, your mute choice and your theme are all saved automatically in your browser and restored next time you open the page. Nothing is uploaded to a server.