Stopwatch, timer and Pomodoro
A stopwatch with laps, a countdown with a gentle sound, and a Pomodoro timer for focused work. It keeps the right time even if you switch to another tab.
Change the times
New times apply from the next session.
Times are worked out from the clock, not by counting ticks, so they stay right in a background tab. Phones may hold back sounds while the screen is off: when you come back, the page catches up at once.
Runs on your device. Nothing is uploaded or saved, so closing the page stops the timers.
Good to know
Work on one thing for 25 minutes, then take a 5-minute break, ideally away from screens. After four rounds, take a longer break of 15 to 30 minutes. Change the times if they do not suit you.
Browsers slow down timers in background tabs, so a timer that counts ticks drifts. This one notes when you pressed start and compares it with the clock each time it updates.
The chime is made on your device, with no sound files. Vibration only works on phones and browsers that support it. Many iPhones do not.
Sources: Duke University Academic Resource Center, "Pomodoro Technique" (created by Francesco Cirillo in the late 1980s, named after a tomato-shaped kitchen timer; 25 minutes of work, a 5-minute break, and a 15–30 minute break after four rounds); MDN Web Docs on the Page Visibility API and on setTimeout (browsers throttle timers in background tabs), the Web Audio API, the Vibration API (support varies by browser) and the Screen Wake Lock API.