About Workout Timer Online

Workout Timer Online is a free web timer for interval training. You set a work duration, a rest duration, a number of rounds and, if your session repeats, a number of cycles. The timer counts each interval down, changes colour at every transition, beeps before the change, and announces the round you are on. That is the whole product.

The same timer is published on a page for each training format — HIIT, Tabata, EMOM, AMRAP, circuits, gym rest periods — and for each sport that runs on rounds, from boxing to Brazilian Jiu-Jitsu. Each of those pages opens with the values that format actually uses, so you are not setting six numbers before you can start. Nothing is locked behind the named page: every value can be changed on any of them.

There is no account, no sign-up, no app to install and no paid tier. Close the tab and nothing is left behind.

Timing a workout is a solved problem that most software solves badly. A round timer is thirty seconds of logic, and yet the usual options are a mobile app that asks for an account before it will count to twenty, a video that forces your whole session into someone else’s intervals, or a web page that stops counting the moment your phone screen dims.

This site started as a personal fix for that last problem: a timer that survives a locked screen, that can be read from across a garage, and that is reachable by typing an address instead of hunting through an app drawer with taped-up hands. It grew into a set of pages because the settings that matter differ by discipline — a boxing round and a Tabata interval are not the same object — and because remembering that IBJJF black belt matches run ten minutes is exactly the kind of thing a tool should remember for you.

The guides came later, for the same reason. Once you have written down what a Tabata interval is, it becomes obvious that most people using the word mean something quite different from the study it is named after. That gap is worth explaining properly, so we do, in the training guides.

Workout Timer Online is written, built and maintained by Hugo Dufour, an independent web developer based in France, operating as a registered sole trader. The registration details, the hosting provider and the formal publication notice are on the legal notice page.

There is no editorial team and no rotating cast of anonymous contributors. The same person writes the code, writes the text, checks the numbers and answers the email. When something on this site is wrong, there is exactly one person to tell, and the address is contact@workouttimeronline.com.

What that means in practice: this is a developer’s site about a tool, not a coaching business. We are precise about the mechanics of intervals, round formats and competition rulebooks, because those are verifiable facts. We do not write training programmes, we do not prescribe workouts for individuals, and we say so again in the disclaimer below.

The countdown does not drift

The naive way to build a timer is to subtract a tenth of a second on every tick. Browsers throttle background tabs, tick intervals arrive late, and after fifteen rounds a timer built that way is visibly behind. Ours stores an absolute end timestamp for the current interval and derives the display from the difference between that timestamp and the current clock on every frame. A late tick shows the correct time rather than a stale one, so a forty-minute session ends when it should.

The sounds are generated, not downloaded

The beeps at the end of an interval are synthesised in the browser with the Web Audio API — oscillators, not audio files. That means no extra network request, no delay on the first beep, and nothing to fail on a gym Wi-Fi network. It also means the sound works after the page has loaded even if the connection drops entirely.

The screen stays awake

Where the browser supports the Screen Wake Lock API, the timer holds a lock while it is running and releases it when you pause. This is the difference between a timer you can leave on a bench and one you have to poke every thirty seconds.

It is usable without looking at it

Every control is reachable with the keyboard, the space bar starts and pauses when the timer is on screen, and phase changes are announced to screen readers through a polite live region. A fullscreen mode blows the countdown up to fill the display so it stays readable from the far side of a room or from the bag.

Nothing is loaded from anyone else

No external fonts, no icon libraries, no social widgets. The only third-party code on the site is audience measurement (Google Analytics and Microsoft Clarity, described in the privacy policy) and the advertising described below. Everything else — markup, styles, script, icons — is served from this domain, which is why the pages weigh a few kilobytes and open on a phone in a basement gym.

The timers are free and are meant to stay free. The site is funded by advertising served by Google AdSense, which pays for the domain, the hosting and the time spent maintaining the tool. Advertising is the only revenue on the site: there is no paid tier, no affiliate programme and no sponsored content. No advertiser has ever been shown a guide before publication, and none has any say over what a page recommends.

Advertising means third-party cookies, and that is described in full — what Google and its partners may set, and how to opt out — in the advertising and cookies section of the privacy policy. Nothing you type into a timer is ever part of that: work, rest, rounds and sets stay in your browser and are never transmitted.

Workout Timer Online publishes a timing tool and reference material about how training formats are structured. It does not provide medical advice, diagnosis or treatment, and nothing on the site is a substitute for a qualified doctor, physiotherapist or coach who has actually seen you train.

High-intensity interval training is demanding on the heart, the lungs and the joints. If you are returning from injury, are pregnant, have a cardiovascular or metabolic condition, or have simply not trained in a long time, speak to a doctor before starting. Warm up, scale the work to your own condition, and stop if something hurts in a way that is not ordinary training discomfort. The numbers in our guides describe what formats typically look like — they are not a prescription for you.