Interval Training Timer for HIIT (Complete Guide)

Interval training is the most efficient form of exercise. It burns more fat, builds more endurance, and takes less time than traditional cardio. But to do it properly, you need an interval timer — a timer that automatically switches between work and rest periods.

What is an interval timer?

An interval timer is a timer that cycles between work and rest periods automatically. Instead of manually starting and stopping a stopwatch, the interval timer tells you when to work, when to rest, and how many rounds you have completed.

Our Interval Timer does all of this for free — no login, no ads, no app to download. It runs in your browser and plays a sound at each transition.

Why interval training is the best workout

Interval training — specifically HIIT (High-Intensity Interval Training) — has been proven by dozens of studies to be the most effective form of exercise for:

• Fat loss — HIIT burns 25–30% more calories than steady-state cardio
• Cardiovascular health — improves VO2 max faster than any other training method
• Time efficiency — a 20-minute HIIT session delivers the same benefits as a 60-minute jog
• Metabolic boost — your body continues burning calories for hours after the workout (the "afterburn effect")
• Muscle preservation — unlike long cardio sessions, HIIT preserves muscle mass

The best interval protocols

30/10 (HIIT standard)

30 seconds of intense work, 10 seconds of rest. Repeat for 8 rounds. This is the most popular HIIT protocol and works for almost any exercise — sprints, burpees, kettlebell swings, or cycling.

40/20 (Endurance HIIT)

40 seconds of work, 20 seconds of rest. This is ideal for building endurance while maintaining intensity. The longer work period challenges your aerobic system, while the short rest keeps your heart rate elevated.

20/10 (Tabata)

20 seconds of all-out effort, 10 seconds of rest. Repeat 8 times for a total of 4 minutes. Tabata is the most intense interval protocol — it was developed by Japanese researcher Izumi Tabata and has been shown to improve both aerobic and anaerobic capacity in just 4 minutes per session.

60/30 (Advanced HIIT)

60 seconds of work, 30 seconds of rest. This is for advanced athletes who can sustain high intensity for a full minute. Use this for complex movements like thrusters, clean and press, or rowing.

How to use an interval timer for different workouts

HIIT

Set your Interval Timer to 30 seconds work, 10 seconds rest, 8 rounds. Choose 3–4 exercises and cycle through them. A typical HIIT session:

1. Burpees — 30s work, 10s rest
2. Jump squats — 30s work, 10s rest
3. Mountain climbers — 30s work, 10s rest
4. Kettlebell swings — 30s work, 10s rest
5. Rest 60 seconds, repeat 3–5 times

Tabata

Set the timer to 20 seconds work, 10 seconds rest, 8 rounds. Pick one exercise and go all-out for each 20-second interval. Tabata is short but brutal — do not underestimate it.

CrossFit-style AMRAP

Set the Countdown Timer for 12–20 minutes and complete as many rounds as possible of a circuit. Track your rounds and try to beat your score next time.

Circuit training

Set the interval timer to 45 seconds work, 15 seconds rest, with one round per exercise. Move through 6–8 exercises, rest 2 minutes, and repeat 3 times.

Tips for effective interval training

1. Warm up properly — 5 minutes of light cardio and dynamic stretching before your first interval
2. Go all-out during work periods — interval training only works if you push hard during the work phase
3. Use the rest periods — actually rest; do not keep moving
4. Track your rounds — knowing your numbers motivates you to improve
5. Cool down — 5 minutes of light movement and stretching after your session
6. Do not overdo it — 3 HIIT sessions per week is enough; your body needs recovery

Why a browser interval timer is better than a phone app

Phone interval timer apps are convenient, but they come with problems: notifications during your workout, battery drain, and the temptation to check messages between sets. A browser-based interval timer like our Interval Timer runs on your computer or tablet, away from your phone. You can see the timer from across the room, and there are no distractions.

Conclusion

Interval training is the most efficient way to exercise, and an interval timer is the tool that makes it possible. No more watching the clock, no more guessing when to rest, no more cutting your workout short. Set your intervals, press start, and train.

Start your interval training now: Interval Timer