Pomodoro Timer

The cycle this timer runs

The timer alternates between exactly two phases, focus and break, and keeps going until you pause or reset. Each phase starts with the full number of minutes you set, counts down to zero, beeps, and hands over to the other phase without any click from you. The completed counter increases at the end of every focus phase, and only then; stopping a focus phase early does not count it.

The card colour tells you which phase you are in at a glance, blue-tinted for focus and green-tinted for break, and the progress bar shows how far through the current phase you are.

How it counts, and what a hidden tab changes

Like the stopwatch and the online timer on this site, the Pomodoro timer is driven by the clock rather than by counting ticks. Pressing Start records the moment the phase should end, the current time plus the minutes left, and every quarter of a second the display is refreshed from the difference between that end moment and the time now. Pause keeps the remaining time to the millisecond and Resume adds exactly that to the clock, so a phase paused five times still lasts the minutes you set, no more and no less.

A hidden tab cannot stretch a phase, because the end moment is fixed, but it can delay the beep. Chrome, for instance, wakes a background tab no more than once a minute after it has been hidden for about five minutes, so a focus phase that ends while you are in another tab may ring up to a minute late; the break then starts from the moment the page woke, with its full length. On a phone, locking the screen suspends the page entirely, and when you unlock it the timer catches up at once, beeping and moving to the next phase if the end has passed.

Changing durations and resetting

• The minute fields are disabled while the timer runs. Press Pause, change them, then Start again; the current phase reloads with the new length.
• Changing a length while the timer is idle updates the display immediately for the phase currently shown.
• Reset stops the clock, switches back to Focus with the full focus length, and sets the completed counter to zero.
• Nothing is saved between visits. The counter and the settings return to their defaults when you reload the page.

Classic Pomodoro schedule compared with this timer

The original method uses 25-minute work blocks with 5-minute breaks and a longer break of 15 to 30 minutes after every fourth block. This timer has no automatic long break, so when the counter shows a multiple of four, pause, set Break to 15 or 20, press Start, and change it back afterwards. Other popular rhythms work the same way: 50 and 10 for writing or coding, 90 and 20 for long creative sessions, 15 and 3 for younger students.

About the beep

The alert is a 0.6-second 880 Hz sine tone generated with the Web Audio API at the moment the phase ends. It plays once per switch and cannot be changed or made longer. If you hear nothing, check the device volume and that the tab is not muted; browsers also require that you have interacted with the page, which pressing Start satisfies.