Pomodoro Timer

How the intervals run

The pattern is 25 minutes of work, then a 5-minute break, four times over, and then a longer break of 15 minutes. It is a rhythm rather than a rule: the point is that the work interval is short enough to start without dread, and the break is short enough that you come back.

Nothing advances by itself except the clock. When an interval ends the timer chimes, sets up the next one and waits for you — because a break that starts while you are still typing is not a break.

Two things this timer gets right

The clock, not the ticks. Time is measured against your computer's clock, not by counting up in the background. Browsers throttle and even freeze hidden tabs, which makes a naive timer run slow; this one re-reads the clock, so if you switch away for ten minutes and come back, it shows ten minutes gone. The display stops repainting while the tab is hidden, but the time does not stop passing.

The screen, only while it runs. While the timer is running the page asks your browser to keep the screen awake, and it releases that the moment you pause, hide the tab or leave. If your browser does not offer it — several do not — the page says so instead of letting you assume.

What a browser tab cannot promise

A background tab may be throttled or frozen by the browser or the operating system, and on a sleeping phone it may be suspended entirely. The time will be right when you return, but the chime can arrive late, or not until you come back. For something that genuinely matters — a meeting, an oven, a medicine — use your device's own alarm, which the operating system guarantees and a web page cannot.

If you want a plain countdown of any length, use the Countdown Timer. For sound to work to, there is White Noise; for an empty screen, Focus Mode.