A free HIIT timer
High-intensity intervals only work if the hard parts are actually hard and the rests are actually timed. This does the timing so you can concentrate on the first part.
Space bar starts and pauses. The screen stays awake while it runs.
What makes it HIIT rather than just exercise
The distinguishing feature is the intensity, not the length. A HIIT interval is meant to be near your limit — the sort of effort you could not hold for much longer than the interval itself. The rest exists so the next one can be that hard too.
If you can carry a conversation during the work period, it is good exercise, but it is not HIIT. That is not a criticism; steady moderate work is excellent for you. It just means the short protocol is not doing what it is meant to do.
A sensible starting point
Thirty seconds on and thirty off, ten rounds, is a fair first session. It is ten minutes of work and it will tell you honestly where your conditioning is.
As you adapt, the usual progression is to shorten the rest rather than lengthen the work — 30 on and 20 off is a meaningful jump from 30 and 30.
Do less of it than you think
Because the intensity is the whole point, the sessions are short and they cost real recovery. Two or three hard sessions a week alongside easier movement is a common pattern, and more is not automatically better.
If you have a heart or joint condition, or you are coming back from a long break, talk to a doctor before starting near-maximal work. That is worth saying plainly rather than burying.
Questions
What does HIIT stand for?
High-Intensity Interval Training: short bouts of near-maximal effort separated by rests that are too short for full recovery. The intensity is what defines it — the specific timings vary enormously between protocols.
How long should a HIIT session be?
Shorter than most people expect. Ten to twenty minutes of actual work is a full session when the intensity is genuinely high. If you can comfortably do forty-five minutes of it, the intensity is not high.
How many times a week should I do HIIT?
Two or three sessions a week is a common pattern, with easier movement on the other days. Hard intervals draw on recovery, so stacking them daily usually makes the sessions worse rather than the results better.
Is a 30-30 or 40-20 split better?
Neither is better in the abstract. Equal work and rest lets you hit a higher intensity in each round; a shorter rest keeps your heart rate elevated across the whole session. Pick based on which quality you are training.
Is this HIIT timer free?
Yes, with no account and nothing to install. The full STATIONS app is free as well — it builds an entire 45-minute circuit with an animated demonstration of every exercise.
STATIONS turns these intervals into a full 45-minute session — nine stations a half, two halves, an animated demonstration of every exercise, and your own SoundCloud or Mixcloud mix running with the clock. You can also start a video call and train with a friend on the other end. Free, no account.
Build a session