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Oneturn

Timer, stopwatch and world clock

Each city checked with zoneinfo

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A dial timer that rings on time in a background tab, a lap stopwatch, an alarm and a world clock with each city's next daylight saving change.

  • 122world clock cities
  • 8timers at once
  • 1/100 sstopwatch precision

Try it here

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Drag the dial to set the minutes. Once it runs, one turn of the dial matches the time you set.

One tap on ‘5 min’ starts the timer

  1. Tap a presetTap one of the 8 buttons under ‘Tap to start’, from ‘1 min’ to ‘1 hour’, and the timer starts right away.
  2. Type an exact timeEnter hours, minutes and seconds under ‘Set exactly’ and press ‘Start’; the teal band on the dial shows the time left and shrinks back toward 12.
  3. Test the soundPick ‘Bell’, ‘Beep’ or ‘Soft’ under ‘Sound’ and press ‘Test sound’ to hear it before the timer ends.
  4. Name and add timersGive a timer a name and use ‘Add a timer’ to run more; when one ends, the alert shows its name.

It can also

What it checks and discloses

City times come from the IANA time zone database, with the 2026 rule changes for Canada, Morocco and Cuba applied separately, and the tests compare every city with Python's zoneinfo.

More in About Oneturn

In a background tab it still rings on time, because it sets one timer for the end

Rules and sources

City times
Uses the IANA time zone data in your browser. The 2026 rule changes for Canada, Morocco and Cuba are built in, so those cities stay right on older browsers, and the world clock says when your browser's data is out of date.IANA change log · Checked Oct 29, 2026
Ringing in a background tab
In a tab hidden for over 5 minutes, Chrome may check timers that keep re-arming themselves only once a minute, so Oneturn works out the time left from the end time.Chrome for Developers: Heavy throttling of chained JS timers beginning in Chrome 88 · Checked Oct 14, 2026
Screen off or another app
When the screen turns off or you switch apps, the browser may freeze the page, and no timer runs while it is frozen.Chrome for Developers: Page Lifecycle API · Checked Oct 14, 2026
Keep screen on
‘Keep screen on’ works from Chrome 84, Safari 16.4, Safari on iOS 18.4 and Firefox 126. Other browsers show ‘This browser cannot keep the screen on’.MDN: Screen Wake Lock API, browser compatibility · Checked Oct 14, 2026
What stays on your device
Timer names and end times, stopwatch laps, alarms, cities and settings are kept in this browser only and never sent to a server.Oneturn Privacy Policy (the six things it stores) · Checked Oct 14, 2026

It cannot ring once the tab is closed or the device sleeps, so use your phone's clock app for an alarm you cannot miss.

3 guides

  1. Why online timers run late in a background tab
  2. Daylight saving time 2026–2027: when clocks change and how time differences shift
  3. Lap time vs split time on a stopwatch

All guides

IANA’s Oct 27 time zone update went in before the Nov 1 change

  1. The world clock now follows Cuba’s decision to skip the November 1 clock change (IANA release 2026f).

  2. From day one, the world clock follows the Canada and Morocco changes up to IANA release 2026e.

  3. Published three guides: background-tab timers, daylight saving in 2026 and 2027, and lap vs split time.

  4. Launched the timer, stopwatch, alarm and world clock in English and Korean.

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