Free tool
HIIT timer
Set your work and rest, pick your rounds and run a full-screen HIIT session with clear sound cues. The default is 40 seconds hard and 20 seconds easy for eight rounds. Nothing to install and no sign up.
Seconds per phase. Raise the work and lower the rest to make it harder.
Save your HIIT sessions and run them anywhere
This page runs one timer at a time. The free Interval Timer app saves every timer you build, casts to the big screen and reads each step out loud.
What is HIIT?
HIIT is high intensity interval training. You alternate short bursts of hard effort with short recoveries, so your heart rate climbs and stays up. Because the work is intense, the sessions are short, often 10 to 25 minutes including the rests. It suits people who want a lot of training effect from a small slot of time.
How to use this timer
Choose a work and rest that match your fitness. Forty seconds hard and 20 easy is a solid start. Pick something you can push, like a bike, rower, skipping rope or bodyweight moves. Press start, go hard on the work phase and keep moving gently through the rest. The screen turns green for work and dark for rest, with a beep on every change.
Pick your work-to-rest ratio
A 2 to 1 work-to-rest ratio, like 40 on and 20 off, is a good middle ground. Shorten the rest for a harder session, or lengthen it when you are learning a movement or coming back from a break. Longer work with equal rest suits steady conditioning. Set the numbers to match the day.
Where the app takes over
If you train with intervals often, the free Interval Timer app saves your sessions so you are one tap from starting. It reads each step out loud, casts to a TV and keeps a history. See the full app, or try the Tabata timer for the classic 20/10 format.
Common questions
How long should a HIIT session be?
Most sessions run 10 to 25 minutes including rests. The effort is high, so you do not need long. Quality of effort matters more than time on the clock.
What is a good work-to-rest ratio for HIIT?
A 2 to 1 ratio like 40 seconds work and 20 rest is a solid default. Shorten the rest to make it harder, lengthen it when learning a movement.
How often should I do HIIT?
Two or three times a week is plenty for most people. It is demanding, so leave easy days or strength work in between rather than stacking hard sessions.
Is HIIT better than steady cardio?
Neither is better, they do different jobs. HIIT saves time and pushes your top end, steady cardio builds an easy aerobic base. Most people benefit from some of both.