Workout Timer

Set your work and rest durations, choose your rounds, and go.

seconds

seconds

total rounds

WORK

00:40

Round 1 of 8

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How to use the timer

Set your work duration (the active interval), your rest duration (recovery between intervals), and the total number of rounds. Press start and the timer automatically alternates between work and rest phases, counting down each one, until all rounds are complete. The phase label turns amber during rest so you can tell at a glance whether to push or recover — useful when your phone is across the room during a workout.

What is interval training?

Interval training alternates short bursts of intense effort with periods of rest or lighter activity. Compared with steady, continuous exercise, intervals let you accumulate more high-intensity work in less time. Research links interval training to improved cardiovascular fitness, better insulin sensitivity, and efficient calorie burning — often in workouts as short as 10–20 minutes. The structure also keeps sessions mentally engaging, since you are always working toward the next rest.

Common interval formats

  • Tabata — 20s work / 10s rest × 8 rounds (4 minutes). A research-backed, very high-intensity protocol.
  • HIIT — 40s work / 20s rest × 8–10 rounds. A flexible, popular middle ground.
  • Circuit training — 45s work / 15s rest × 6–12 rounds. Great for moving between exercises or stations.
  • Boxing rounds — 180s work / 60s rest × 3–12 rounds. Classic for bag work and conditioning.

HIIT vs steady-state cardio

Neither is strictly better — they serve different goals. HIIT is time-efficient and excellent for improving anaerobic capacity and burning calories quickly, but it is demanding and needs adequate recovery, so 2–3 sessions per week is plenty for most people. Steady-state cardio (a continuous jog or bike ride) is gentler, easier to recover from, and builds aerobic endurance, making it ideal for active recovery days and beginners. A balanced routine often includes both.

Frequently asked questions

What is the best work-to-rest ratio?

It depends on your goal. A 2:1 work-to-rest ratio (e.g. 40s work / 20s rest) builds conditioning and is widely used in HIIT. A 1:1 ratio suits moderate effort, while a 1:2 ratio (more rest than work) is better for maximal-intensity sprints where full recovery matters. Beginners should start with more rest and shorten it as fitness improves.

Is Tabata good for beginners?

True Tabata is extremely intense — 20 seconds of all-out effort with only 10 seconds of rest, repeated 8 times. Beginners are usually better off starting with longer rest periods (for example 30s work / 30s rest) and building up. You can use this timer to set any beginner-friendly interval you like.

How long should a HIIT workout be?

Because of its intensity, a HIIT session is typically short — 10 to 25 minutes including warm-up is plenty for most people. Quality matters more than duration: a focused 15-minute session at high effort beats a longer, half-hearted one. Aim for 2–3 HIIT sessions per week with recovery days in between.

Does the timer keep running if I lock my screen?

The timer runs in your browser, so behaviour depends on your device and browser settings — some mobile browsers pause background tabs to save battery. For best results, keep the tab open and your screen awake during your workout.

How many rounds should I do?

Start with what you can complete with good form — often 4–8 rounds for beginners — and add rounds as your fitness improves. The right number depends on the exercise intensity, your conditioning, and your available time. It's better to finish strong than to burn out halfway.

Disclaimer: Interval and high-intensity training is demanding. This tool is for general informational purposes only. Consult a doctor before beginning a new exercise programme, especially if you have a heart condition, injury, or other health concern.

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