Online Interval Timer
A free workout timer for HIIT, Tabata, boxing, and circuit training — set your active and rest time, then press start right in your browser.
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Need More Reliable Timing On Mobile?
Download the app if you want saved routines and more reliable timing when your phone goes into the background.
What Is Interval Training?
Interval training alternates short periods of high-intensity exercise with fixed periods of low-intensity recovery or rest. Because every work and rest phase follows a set duration, it improves both aerobic and anaerobic fitness in less time than steady-state cardio. HIIT, Tabata, circuit training, and boxing rounds all use this pattern — and all of them depend on accurate timing to keep the workout effective.
Why Use an Online Interval Timer?
Keeps every round consistent
Watching a clock by hand breaks your focus and makes rounds uneven. A timer enforces exact active and rest periods, so your training intensity stays where it should be.
Hands-free audio cues
Turn on the boxing bell to hear when a set starts, when rest begins, and when the workout finishes — no need to stare at the screen between exercises.
Nothing to install
It runs in any modern browser on phone or desktop. No app download, no account, and no setup beyond choosing your timings.
How To Use This Interval Timer
1. Pick a preset or set timings
Choose a one-tap preset such as 20s/10s Tabata, or enter your own Active Time, Rest Time, and number of Sets. The total workout time updates automatically.
2. Press Start
The timer alternates Active and Rest phases through every set. You can pause and resume at any time, or restart the full sequence when you are done.
3. Enable alerts
Turn on the boxing bell for audio cues at each phase change, or enable desktop notifications so you know when a set finishes even in another tab.
Tip: scroll until the timer fills your screen to use it in full screen during your workout.
Popular Interval Setups
The timer includes one-tap presets for the most common interval formats. The default setup is a classic Tabata — just press Start.
Tabata — 20s / 10s
20 seconds of all-out effort followed by 10 seconds of rest, repeated for 8 sets.
HIIT — 30s / 30s
Equal work and rest periods that balance intensity with recovery for longer sessions.
Circuit — 40s / 20s
40 seconds of work per station with 20 seconds to transition — also available as a 45s / 15s preset.
Strength — 60s / 30s
Longer work blocks with enough rest to reset form and load weight between efforts.
Boxing — 3min / 1min
Three-minute rounds with one minute of corner rest, paired with the boxing bell for authentic round cues.
Pomodoro — 25min / 5min
Focused work sprints and short breaks for study and deep work sessions away from the gym.
Interval Timer Online FAQ
What is an online interval timer?
It is a workout timer that runs directly in your web browser. It counts down alternating active and rest periods for a set number of rounds, so you can follow HIIT, Tabata, circuit, or boxing workouts without watching a clock.
Do I need to download or install anything?
No. The timer works in any modern browser on desktop or mobile — just open the page, choose your timings, and press Start. There is no account and no installation required.
Is this timer good for HIIT and Tabata workouts?
Yes. It includes one-tap presets for common formats, including 20/10 Tabata (the default setup), 30/30 HIIT, 40/20 circuits, and 3-minute boxing rounds. You can also enter any custom active time, rest time, and number of sets.
Does it make sound when intervals change?
Yes. Enable the boxing bell to hear distinct sounds when a set starts, when rest begins, and when the workout finishes. Desktop users can also enable browser notifications when a set completes.
Can I use it on my phone?
Yes, it runs in mobile browsers. If you want saved routines or more reliable timing while your phone screen is off or in the background, the free Interval Timer X Workout Timer app is available for iOS and Android.