The best interval timer: criteria, options and protocols
A good interval timer gives you a loud, distinct cue for each switch, digits readable from a few metres away, a short prep countdown and a round counter, with no subscription. A browser timer on a propped-up phone or a laptop covers this for most home and gym sessions.
Free tool: Open the free interval timer →
Start now: TabataEMOM3 min round1 min rest20 min AMRAP
What separates a good interval timer from a bad one
During intervals you are breathing hard, possibly sweating into your eyes, and sometimes in a room with music on. You should not have to look at the timer at all. That changes the priorities compared with a desk timer.
- Distinct audio cues for work, rest and the final seconds, loud enough to hear over music.
- A prep countdown (often 10 seconds) so you can get into position after pressing start.
- Big digits and a clear colour change between work and rest, readable from 2 to 3 metres.
- A visible round counter, so you never have to remember whether that was round 5 or 6.
- Easy editing of work, rest and rounds without wading through menus between sets.
- No subscription or paywall for basic intervals. Work, rest and rounds should be free.
- The screen stays awake while it runs, so your phone does not lock mid-session.
Interval timer options compared
| Option | Cost | Audibility | Readability at distance | Best for |
|---|---|---|---|---|
| Browser interval timer | Free | Good, uses device speaker | Good in full screen | Home workouts, garage gyms, laptops and phones |
| Phone app | Free to subscription | Good | Depends on screen size | People who want saved workout libraries |
| Gym wall clock | Expensive, bought by the gym | Very good, built-in buzzer | Excellent | Group classes and shared gyms |
| Sports watch | Expensive device | Vibration, quiet beeps | Wrist only | Running intervals outdoors |
If your gym has a wall clock with intervals programmed, use it; nothing beats a large LED display with a buzzer. For running outside, a watch with vibration is more practical than anything on a screen. For everything in between, a free browser timer does the job without an install or a subscription.
Common interval protocols and their total time
Total times below exclude warm-up and cool-down. Add 5 to 10 minutes of each.
| Protocol | Work / rest | Rounds | Total time | Typical use |
|---|---|---|---|---|
| Tabata | 20 s / 10 s | 8 | 4 min | One exercise, maximum effort |
| EMOM | Start a set every minute, rest for what remains | 10 to 20 | 10 to 20 min | Strength skill work, conditioning |
| 30/30 | 30 s / 30 s | 10 to 20 | 10 to 20 min | Beginners, steady circuits |
| 40/20 | 40 s / 20 s | 10 to 15 | 10 to 15 min | General HIIT circuits |
| 45/15 | 45 s / 15 s | 8 to 12 | 8 to 12 min | Harder circuits, short transitions |
| AMRAP | Fixed time, no set rest | 1 block | 10 to 20 min | As many rounds as possible of a set circuit |
| Boxing rounds | 3 min / 1 min | 3 to 12 | 12 to 48 min | Bag work, pad work, shadow boxing |
Tabata takes its name from Izumi Tabata, whose 1996 study used 20 seconds of very hard effort and 10 seconds of rest for eight rounds. The study used a cycle ergometer at very high intensity, so a casual 4 minute circuit at moderate pace is a different thing, though still a useful workout.
Setting each one up in ClockAura
- Tabata: open the Tabata timer, which is preset to 20 s work, 10 s rest, 8 rounds. Press Space to start after the prep countdown.
- EMOM: open the EMOM timer and set the number of minutes. A cue plays at the top of each minute.
- 30/30, 40/20, 45/15: open the interval timer, enter work, rest and rounds, and save it as you go.
- AMRAP: use a plain countdown such as /t/20m?label=AMRAP and count rounds yourself.
- Boxing: interval timer with 3 min work, 1 min rest and the number of rounds you want, or use /t/3m?label=Round for a single round.
Voice cues count down the last seconds, and the wake lock keeps the screen on while the timer runs. Press F for full screen so the digits fill the display.
Practical tips for using an interval timer well
- Set the volume before the first round. Turning it up mid-burpee does not happen.
- Put the device at eye level when standing, not on the floor.
- If you pair exercises, write them down in order. The timer tracks time, not which move is next.
- Count rest as rest. If you need longer, change the protocol rather than cutting work short.
Honest limits
ClockAura does not store workout history, heart rate or a library of exercises, and it has no app store app. If you want logged progress over months, a dedicated training app or a notebook is the right tool. What it does offer is free, quick intervals that work on any device with a browser.
Frequently asked questions
What is the difference between Tabata and HIIT?
Tabata is one specific interval pattern, 20 seconds on and 10 seconds off for 8 rounds. HIIT is the broader category of high intensity intervals and includes many other work and rest splits.
Can I hear the interval timer over music?
Usually, if the device volume is high and the speaker is not covered. In a loud gym, a Bluetooth speaker or the gym's own wall clock may be more reliable.
Does the screen stay on during intervals?
Yes, while the timer is running it asks the browser to keep the screen awake. Some battery saver modes can override this, so turn those off for the session.
Is there a prep countdown before the first round?
Yes, there is a short countdown before work starts, so you can get into position after pressing start.