The Interval Timer That Coaches Your Whole Workout
An interval timer is the simplest piece of gym equipment you will ever own, and possibly the most important. Instead of counting repetitions or watching a wall clock, you train against time itself: a work period where you give full effort, a rest period where you recover just enough, and a set number of rounds that repeat until the session is done. IntervalIQ is a free online interval and Tabata timer built around that idea. You set four numbers — work seconds, rest seconds, rounds, and an optional get-ready countdown — and the timer runs the entire session hands-free, calling every phase change with clear audio beeps generated live in your browser. Whether you are midway through a kettlebell complex, holding a plank, or coaching a full class, you never need to look at the screen to know where you are.
Interval training earned its reputation because it works. Short, intense efforts separated by incomplete recovery push both your aerobic and anaerobic systems in a fraction of the time steady-state cardio demands. A classic four-minute Tabata protocol can deliver measurable fitness gains, and longer high-intensity interval training (HIIT) sessions of fifteen to thirty minutes fit into lunch breaks, hotel rooms, and living rooms. But the method only works if the timing is honest. Counting seconds in your head while exhausted is notoriously unreliable — everyone counts faster when they are tired. A dedicated interval timer removes the negotiation. The beep starts the work, the beep ends it, and your only job is to move.
Custom Work, Rest and Rounds for Any Protocol
Every training style has its own rhythm, so IntervalIQ does not lock you into one format. Work intervals can run from a single second to a full hour, rest can be anything from zero to an hour, and you can stack up to ninety-nine rounds. A sprinter might program thirty seconds of effort with ninety seconds of recovery for six rounds. A CrossFit athlete might set forty seconds on and twenty seconds off across a ten-station circuit. A yoga practitioner can use gentle two-minute holds with thirty-second transitions. A boxing coach can run three-minute rounds with one minute of rest, exactly like a real bout. The session breakdown panel updates as you type, showing total workout time, total time working, total time resting, and the number of phases, alongside a visual strip where each block is one phase — red for work, green for rest, amber for the get-ready countdown — so you can see the shape of your session before you start it.
Small details matter when you are setting up between exercises. Quick-tweak buttons nudge the work time up or down by five seconds and add or remove a round without typing. Invalid entries are handled gracefully: type a negative number or something impossible and IntervalIQ clamps it to a safe value and tells you what happened, rather than crashing or silently refusing to start. If you set rest to zero, rounds run back to back with no breaks at all, which is exactly what continuous circuits and EMOM-style training demand. If you set the get-ready countdown to zero, the workout begins the instant you press Start — useful when your hands are already on the bar.
Tabata, EMOM and HIIT Presets, Ready in One Tap
If you do not want to build a session from scratch, the preset row loads proven formats instantly. The Tabata preset follows the original protocol studied by Dr. Izumi Tabata: twenty seconds of maximal work, ten seconds of rest, eight rounds — four minutes that feel considerably longer. The EMOM preset runs forty-five seconds of work and fifteen seconds of rest for ten rounds, so every round fills exactly one minute; EMOM, short for Every Minute On the Minute, is a staple of functional fitness because the clock itself sets the pace and any leftover seconds become your rest. The HIIT Burner preset uses forty seconds on and twenty seconds off for twelve rounds, a forgiving ratio that sustains high output across a twenty-two-minute session. Boxing Rounds delivers twelve three-minute rounds with one-minute rests, and Gentle Start offers thirty-thirty intervals for six rounds for beginners, warm-ups, or active recovery days. Presets are starting points, not cages: load one, then edit any number to make it yours.
Web Audio Countdown Beeps You Can Hear Across the Room
Sound is the soul of an interval timer. IntervalIQ synthesizes its beeps with the Web Audio API, the same technology behind browser-based instruments and games, so tones are generated mathematically on your device — no audio files to download, no buffering, and crystal-clear timing. During the final three seconds of any phase you will hear short countdown beeps, the timer's way of saying get ready. A brighter two-tone signal marks the start of work, a lower signal marks rest, and a long finishing tone celebrates the end of the session. Because the beeps are synthesized, they stay perfectly in sync with the visual countdown even during long workouts. A sound toggle lets you mute the timer for quiet environments like offices or sleeping households, and a Test Beep button confirms your volume before the workout starts — no more discovering a muted phone thirty seconds into round one. One browser rule to know: audio can only begin after you interact with the page, which is why pressing Start unlocks the sound for the whole session.
Big-Screen Display Mode for Gyms, Classes and Garage Training
A phone propped against a water bottle is fine for solo training, but group sessions need a clock everyone can read. IntervalIQ's big-screen mode uses the fullscreen API to expand the stage across your entire display — a television, a projector, a tablet on a tripod, or a laptop at the end of the gym — while the digits grow to fill the space and the settings panels step aside. The stage also changes colour with the phase: a red glow for work, green for rest, amber during the get-ready countdown, and blue when you are done, so athletes can read the session state from peripheral vision without parsing numbers. Coaches use this mode to run stations without shouting times; home users cast it to a TV and train facing the screen instead of a phone on the floor. Press Esc or the Big Screen button again to return to the normal view.
How to Run Your First Session
Getting started takes under a minute. First, pick a preset that matches your goal, or enter your own work, rest, and round values. Second, check the session breakdown so the total time fits your schedule — a Tabata finisher is four minutes, while the HIIT preset runs twenty-two. Third, tap Test Beep and set a volume you can hear over music and breathing. Fourth, place your device where you can see it, or switch on big-screen mode, and press Start. During the workout the stage shows your current phase, the round you are on, a progress bar for the whole session, elapsed time, and what comes next. Pause any time life interrupts, skip forward if you need to jump a phase, or reset to start over. When the final work interval ends, the finishing tone plays and the stage turns blue: session complete.
A few programming tips will help you get more from any interval timer. Beginners should start with work-to-rest ratios of one-to-two or one-to-one and build toward one-to-half as fitness improves. Keep at least one truly easy interval day between hard sessions, because the adaptations happen during recovery, not during the beeps. If you are new to Tabata, remember the original protocol was performed at an intensity most people cannot sustain at first — using it at eighty percent effort for a few weeks is smart training, not failure. Finally, write your numbers down. The session you repeat and gradually extend beats the exotic workout you try once.
IntervalIQ runs entirely in your browser. There is no account to create, nothing to install, no subscription, and no watermark — just unlimited free usage on any device with a modern web browser. Your settings live only on your screen; close the tab and nothing about your workout has been sent anywhere. Bookmark it on your phone's home screen, open it on the gym television, or keep it in a browser tab next to your training log. Set the intervals, press Start, and let the beeps coach you through every round.
Frequently Asked Questions
What is an interval timer and how does IntervalIQ work?
An interval timer alternates timed work periods with timed rest periods for a set number of rounds. In IntervalIQ you set your work time, rest time, rounds and an optional get-ready countdown, press Start, and the timer runs the whole session automatically with beeps marking every phase change.
What are the Tabata, EMOM and HIIT presets?
Tabata is 20 seconds of work and 10 seconds of rest for 8 rounds. EMOM (Every Minute On the Minute) here runs 45 seconds of work and 15 seconds of rest for 10 rounds so each round fills exactly one minute. The HIIT Burner preset uses 40 seconds of work and 20 seconds of rest for 12 rounds. Every preset can be edited after loading it.
Do the countdown beeps work on phones and tablets?
Yes. IntervalIQ generates its beeps with the Web Audio API directly in your browser, so no sound files are downloaded. Browsers require one tap before audio can play, so press Start (or the sound test) once and every beep for the session will work, including on phones and tablets.
What is big-screen display mode?
Big-screen mode expands the timer to fill your display using the fullscreen API and hides the settings, so the countdown can be read from across a gym floor or classroom. Press the Big Screen button to enter it and Esc or the button again to exit.
Can I use IntervalIQ without rest periods or a warm-up countdown?
Yes. Set rest to 0 and rounds run back to back with no breaks, which suits EMOM-style and circuit training. Set the get-ready countdown to 0 and the workout starts the instant you press Start.
Is IntervalIQ free and do I need an account?
IntervalIQ is completely free with unlimited usage. There is no signup, no account, no paywall and no watermark. Everything runs locally in your browser and no workout data ever leaves your device.