Loading page
About this tool
Classic 20-second work, 10-second rest Tabata timer with custom rounds, multiple sets and a prep countdown.
The Tabata protocol is eight rounds of 20 seconds of maximal work separated by 10 seconds of rest — exactly four minutes, at a 2:1 work-to-rest ratio. This timer runs that structure with a prep countdown and optional extra sets, and reports total working time, total rest and the work-to-rest ratio whenever you change the intervals. It comes from Izumi Tabata's 1996 study on Japanese speed skaters, where the work bouts were performed at about 170 percent of VO2max.
Open Tabata Interval Timer on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
Opens on 20 seconds work, 10 seconds rest, 8 rounds — the tested structure, not an approximation.
Session length, working time and rest time update as you edit any interval.
Chain several blocks with a defined break and see the full phase-by-phase schedule.
Eight rounds of 20 seconds of all-out effort with 10 seconds of rest between them, totalling four minutes. In the original 1996 study the work intervals were performed at roughly 170 percent of VO2max, which is far harder than typical interval training.
One classic block is 4 minutes: 8 rounds of 30 seconds, of which 2 minutes 40 seconds is work and 1 minute 20 seconds is rest. Most sessions stack two to four blocks with a rest between them, giving 15 to 25 minutes including breaks.
It keeps the timing but not the stimulus. The protocol's effect depends on the intervals being genuinely maximal; at a moderate effort a 20/10 block is simply short interval conditioning, which is still useful but should not be expected to produce the same results.
Movements you can perform at full effort without technique breaking down under fatigue — assault bike, rower, sprints on a stationary bike, air squats, or burpees. Avoid heavy or technical barbell lifts at this intensity, and speak to a qualified professional before starting maximal interval work.