HIIT Timer
Free online HIIT timer, Tabata timer and interval timer in one. Set work, rest, rounds and sets, then hit start. No signup, no ads.
0 = no rest (EMOM style)
20s work / 10s rest × 8 rounds — 3m 50s total.
- 1Work · round 120s
- 2Rest · round 110s
- 3Work · round 220s
- 4Rest · round 210s
- 5Work · round 320s
- 6Rest · round 310s
- 7Work · round 420s
- 8Rest · round 410s
- 9Work · round 520s
- 10Rest · round 510s
- 11Work · round 620s
- 12Rest · round 610s
- 13Work · round 720s
- 14Rest · round 710s
- 15Work · round 820s
Tip: press Space to start/pause, R to reset, N to skip an interval.
What this interval timer does
This is a general-purpose interval timer rather than a fixed routine. You choose the work seconds, the rest seconds, how many rounds, and — if you want a longer session — how many sets and how long to rest between them. A warm-up and cool-down can be bolted on either end. The timer expands all of that into a single sequence and runs it, showing the seconds left in the current interval, whether you should be working or resting, and which round you are on out of how many.
The same tool covers the three things people usually search for separately: a HIIT timer for work/rest circuits, a Tabata timer for the 20/10 × 8 protocol, and a plain interval timer for anything else — boxing rounds, EMOM lifting, sprint repeats, or a 3-minute-on, 1-minute-off rowing piece.
Where the Tabata protocol comes from
The 20-seconds-on, 10-seconds-off, eight-rounds format is named after Tabata et al. (1996), published in Medicine & Science in Sports & Exercise. Trained young men cycled at roughly 170% of VO2max for 20 seconds, rested 10, and repeated it seven to eight times, four days a week for six weeks. That group improved both anaerobic capacity and VO2max, while a moderate-intensity group cycling for 60 minutes improved aerobic capacity only.
Two honest caveats worth keeping in mind. The study used a mechanically braked cycle ergometer with a small, already-trained sample — not bodyweight burpees in a gym class — so a "Tabata" circuit of eight different exercises is borrowing the clock, not the protocol. And 170% of VO2max is a supramaximal effort: by design you should be unable to hold the pace by the last round. The preset here gives you the timing faithfully; the intensity is on you.
Choosing work, rest and rounds
Think in ratios. A 2:1 work-to-rest ratio (20/10, 40/20) is deliberately incomplete recovery and gets brutal fast. A 1:1 ratio (30/30, the Classic HIIT preset) is the common middle ground for circuits and conditioning. A 1:2 or 1:3 ratio (30/60, 30/90) keeps each effort genuinely maximal and is the right place for beginners and for sprint work, where quality matters more than accumulated fatigue. EMOM is a fourth shape entirely: fixed 60-second windows where your rest is whatever time you save by working faster.
Sets exist for longer sessions. Six rounds of 40/20 is one block; run three sets of that with 90 seconds between them and you have an 18-minute workout with structured recovery instead of one long grind.
How often to do HIIT
Two or three sessions a week is the usual ceiling for most people, spread out rather than stacked. Interval training is time-efficient precisely because it is hard, and hard sessions carry a recovery cost — the mistake beginners make is doing five of them in week one and none in week three. The CDC adult activity guidelines let vigorous activity count double toward the weekly target, so 75 vigorous minutes satisfies the same requirement as 150 moderate ones. If you are new to intense exercise, have a heart or joint condition, or are returning after a long break, talk to a clinician before doing all-out intervals.
The part the timer cannot do
Four minutes is not the hard part — showing up on Tuesday for the eleventh week is. Because HIIT sessions are so short, they are unusually easy to postpone: there is no sunk cost in a gym trip to protect. Anchoring the session to something you already do daily and checking it off is what turns it into a routine, which is the same argument we make in how to make exercise a habit. HabitBox is a habit tracker for iOS and Android — one tap to log the session, no account needed, and your data stays on your device — so the streak does the remembering for you.
Frequently asked questions
What is a HIIT timer and how is it different from a stopwatch?+
A HIIT timer is an interval timer: instead of counting up from zero, it counts down repeating blocks of hard work and recovery, then tells you when to switch. That matters because during high-intensity work you cannot reliably watch a clock and do the maths — you need something to shout 'go' and 'stop'. This tool lets you set the work seconds, rest seconds, number of rounds, optional sets, a rest between sets, and an optional warm-up and cool-down, then runs the whole sequence automatically with a phase label and a round counter.
What are the real Tabata timer settings?+
20 seconds of work, 10 seconds of rest, repeated 8 times. That is the protocol Izumi Tabata and colleagues used in their 1996 study at the National Institute of Fitness and Sports in Kanoya, Japan, and it is what the Tabata preset here loads. One caveat almost every 'Tabata' class skips: in the original study the work intervals were performed on a cycle ergometer at about 170% of VO2max — an all-out effort that leaves you unable to continue by round 7 or 8. If you can chat through your 20 seconds, you are doing a 20/10 interval workout, not Tabata intensity.
Why does the Tabata preset show 3:50 instead of 4 minutes?+
Because this timer stops at the end of the last work interval rather than making you sit through a final 10-second rest with nothing after it. Eight 20-second work rounds is 160 seconds, plus seven 10-second rests between them is 70 seconds — 230 seconds, or 3:50. The familiar '4 minutes' figure counts that trailing rest. Nothing about the training stimulus changes; you just stop 10 seconds earlier.
What is EMOM and how do I set it up here?+
EMOM stands for Every Minute On the Minute: you start a set number of reps at the top of each minute and whatever time is left over is your rest, so the faster you work the longer you recover. Load the EMOM preset (60 seconds of work, 0 rest, 10 rounds) and the timer will beep once per minute for 10 minutes. To run an E2MOM, set work to 120 seconds. Because rest is set to zero the timer flows straight from one round into the next — exactly how an EMOM should feel.
What work-to-rest ratio should I use as a beginner?+
Start at 1:2 or even 1:3 — 30 seconds of work to 60 or 90 seconds of rest — rather than the 2:1 ratio Tabata uses. The point of interval training is that the hard bits are genuinely hard, and that only happens if you recover enough to repeat the effort. As your fitness improves, shorten the rest before you lengthen the work. Two or three HIIT sessions a week is plenty for most people; the intensity is what makes it effective and also what makes it costly to recover from.
Will the timer keep running if my screen locks?+
Browsers throttle background tabs, so if your phone locks or you switch apps the countdown can drift or pause. Keep this tab in the foreground for the duration of the workout, and turn the beep on so you can hear the phase changes without staring at the screen. The timer runs entirely in your browser — nothing is uploaded, and there is no account or signup.
Three sessions a week, actually done
HIIT works because it is short — which is exactly why it is easy to skip. HabitBox puts a one-tap check-in on your home screen so 'Tuesday intervals' becomes a streak you can see instead of a plan you keep rewriting.
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