Burst is an interval timer and a field-test logbook. Free, no account, in 10 languages.

EVERY INTERVAL FORMAT
Work/rest intervals, pyramids, distance sessions, Tabata, HIIT, boxing rounds, circuits. Set durations on a wheel, name the exercises of each round, add a warm-up, and see the total time before you start.

RANDOM BEEPS
Random-cue mode drops unpredictable signals into each work phase, at three intensities. Train reaction: strike on the beep, sprint on the beep, change direction on the beep. A feature you will not find in a standard interval timer.

FIELD TESTS, WITH THE MATH
Léger 20 m shuttle run (beep test), 30-15 Intermittent Fitness Test, Gacon 45/15, Yo-Yo IR1 and IR2, Cooper and half-Cooper, 2 km, T-Test, repeated sprints, BOLT, FTP. Burst runs the exact protocol, then computes your aerobic speed and estimated VO₂max and places you on a benchmark by sex and age.

ONE PHONE FOR THE WHOLE TEAM
In team mode you enter up to 40 names before the test. During the run, tap the name of whoever stops: each athlete gets their own level and aerobic speed, and the ranking goes into the history. Built for PE classes, clubs and strength coaches.

YOUR SESSIONS WITHIN REACH
90 ready-made sessions, sorted by sport and by energy system (VO₂max, threshold, anaerobic, recovery), search, filters, and favorites to bring back your own intervals in one tap.

PROGRESS
The history keeps every session, every test result and how it felt. Your aerobic speed and training paces update with each test.

SIMPLE
One screen per task, digits you can read from three meters, clean sounds, a timer that keeps running with the screen locked. Works offline.

Burst is free and supported by ads. No account, no session data sent anywhere: everything stays on your phone.