The Pomodoro Technique: 25 minutes on, 5 minutes off
The method, devised by Francesco Cirillo in the late 1980s and named after his tomato-shaped kitchen timer, breaks work into pomodoros: 25 minutes of single-task focus, then a 3–5 minute break. After four pomodoros you take a longer break of 15–30 minutes. A pomodoro is indivisible: if it is interrupted, it is voided rather than paused, and you start a fresh one. The defaults here, 25/5 with a 15-minute long break every fourth cycle, are Cirillo's.
The point of the short unit is not that 25 minutes is magic but that it is short enough to start without dread and long enough to get somewhere, and the fixed break makes rest a rule rather than a reward you keep postponing. Many people adjust the numbers; the presets below give the common variants.
How this timer runs the cycle
Press Start and a focus session counts down with a red tint and the label FOCUS. At zero the alarm rings once and the break starts by itself, turning green; when the break ends a softer chime plays and the timer waits for you to press Start again, so a focus session only begins when you are actually back at the desk. The counter under the digits reads Cycle 2 / 4, meaning the second focus of the four before the long break, and the long break is shown in blue.
Skip moves to the next period immediately; a skipped focus does not count as completed. Cancel (R) returns to Cycle 1. Settings changed while a session runs take effect from the next focus session, so the one on screen keeps its length. Pause stops the clock, but the technique's advice is to avoid pausing a pomodoro: if something interrupts you for more than a moment, Cancel and start a new one.
Choosing lengths: 25/5, 50/10, 45/15, 90/20
25/5 is the original and suits tasks with frequent natural stopping points, such as email, revision or admin. 50/10 keeps the same 5:1 ratio with fewer interruptions, which many programmers and writers prefer once they are in flow; it is also the usual "study timer" setting. 45/15 matches a school period with a real break and the 3:1 ratio some find more sustainable. 90/20 follows the roughly 90-minute ultradian cycle of alertness that sleep researchers describe, for deep work that needs a long run-up; two such blocks are a full morning.
The long break after every fourth cycle is 15 minutes for 25/5, 20 for 50/10 and 30 for the longer presets, staying within Cirillo's 15–30 minute range. Custom lengths go from 1 to 180 minutes of focus and 1 to 60 of break, and the long-break interval from 1 to 12 cycles. Whatever you choose, the point is to keep the ratio and the rhythm, not to maximise minutes.
Why the breaks matter: what the research says
Attention is not a steady resource. Ariga and Lleras (Cognition, 2011) showed that performance on a 40-minute vigilance task declined steadily for people who worked straight through but held up for those given two brief, unrelated diversions; a short switch resets the goal and the decline restarts from a higher level. That is the mechanism the 5-minute break relies on.
Comparing systematic Pomodoro breaks with breaks taken "when I feel like it", Biwer and colleagues (British Journal of Educational Psychology, 2023) found that students on the fixed schedule reported less fatigue and higher concentration and finished with similar task performance in less total time, because self-regulated breakers tended to work on past the point of diminishing returns. The timer makes the schedule automatic so you do not have to judge that point yourself.
What to do on a break (and what not to)
Stand up, walk, drink water, look out of a window; the 20-20-20 rule for screen eyestrain, looking 20 feet away for 20 seconds, fits a break exactly. Stretch the neck and shoulders. The break works best when it is different in kind from the work: physical rather than mental, away from the screen rather than at it.
Avoid opening messages, social feeds or news: those are tasks in disguise, they pull attention into new threads that are hard to drop after five minutes, and the break then becomes a switch rather than a rest. Keep a scrap of paper for thoughts that arrive mid-focus so they do not force a detour. Use the long break for a real meal or a walk outside.
Sounds, background tabs and phones
The end of a focus session plays the alarm sound you choose, Beep, Bell, Digital, Soft, Cuckoo, Chime or Pipe, once when the break starts automatically; the end of a break plays the Soft chime, and when the timer is waiting for you it repeats until you press Start, Space or Esc. All but the cuckoo are generated in the browser and work offline; the cuckoo is a short clip fetched once and kept. None keeps everything silent except the tab title, colour change and desktop notification.
The end time of each period is fixed when it starts, and the chime is pre-scheduled on the browser's audio clock, so a background tab on a computer changes period and rings on time even though Chrome slows hidden tabs. The tab title shows the countdown and the period, for example "24:32 · Focus". On a phone, Keep screen on holds the screen awake during a session; on an iPhone keep the tab in front, because Safari pauses hidden pages, and iOS 17+ plays the chime through the silent switch.
Settings, today's count and sharing a setup
Today's completed pomodoros and focus minutes are shown under the timer and reset at midnight; only focus sessions that ran to the end count, so skipping does not inflate the number. The lengths, the auto-start switches and the count are kept on this device, and a running session survives a reload or a closed tab: the page restores it, and if a period ended while you were away it tells you and rings once.
Every setup has a link: ?f=50&s=10&l=20&i=4 is the 50/10 preset. Share link copies it, so a study group or a class can use identical settings, and bookmarking it opens the timer ready. No account, no server, no task list: this is the timer alone.