Timers
20 Minute Timer
A twenty-minute countdown timer with an alarm at zero — built for a power nap, a focused study sprint, or timing a quick bake without watching the oven.
Countdown timer
Alarm and notifications
A short tone plays automatically when the timer ends, synthesised in your browser — nothing is downloaded or streamed.
Works even if you switch tabs
This timer tracks the clock time it should finish at, not a count of ticks, so switching tabs or locking your device never makes it run late. The tab title above shows the time left even while you’re looking at something else.
Pick a length and go. Tap one of the one-minute-through-one-hour presets for the durations people set most often — a tea timer, a plank hold, a study sprint, a nap — or dial in an exact hours/minutes/seconds length for anything else. The clock counts down in large, unambiguous digits, and an alarm you can hear (not just see) fires the moment it reaches zero.
Why this timer doesn't drift in a background tab
A browser deliberately slows down a page you've switched away from, throttling its timers to save battery — often to once a second, and on a phone that gets locked or a laptop that sleeps, sometimes stopped completely for minutes at a stretch. A countdown timer that works by decrementing a number on every tick inherits that throttling directly: miss enough ticks and the display reads several seconds, or worse, slow by the time you look at it again — right when you've actually switched away, which is the entire point of running a timer in a tab instead of watching a clock.
This tool sidesteps the problem by never counting down at all. The instant you press Start, it records the real clock time the run is due to finish — not a number it plans to subtract from repeatedly. Every time the display needs to update, it works out the remaining time fresh, by comparing that fixed target against the current time. The repeating tick you see every quarter-second on screen is purely there to repaint the display; it is never the thing deciding how much time is left. Set 20 minutes, put your phone in your pocket, and come back at 20 minutes exactly (or 25, if you got distracted) and the timer will already say it's finished, because the answer was never computed from ticks in the first place.
5 minute timer, 20 minute timer, or any length in between
The presets across the top cover the durations most people search for by name: a 5 minute timer for tea or a stretch, a 10 minute timer for a warm-up or an exam section, a 20 minute timer for a nap or a study sprint, and so on up to a full hour. Tapping one starts that exact length immediately — there's no second confirmation step. If none of the nine fit, the hours/minutes/ seconds fields beside them accept any length at all; enter it and press Start.
The alarm, and how to silence it
When the countdown reaches zero, a short tone plays automatically, synthesised directly in your browser rather than streamed or downloaded — nothing here ever makes a network request, so the alarm works offline once the page has loaded and there is nothing to fetch that could fail or lag. The browser tab's title also updates to show the time remaining, and then that it finished, which is the detail that actually reaches you while you're reading something in a different tab: a toast inside a tab you've switched away from goes unseen, but a title bar reading "Done! – Countdown Timer" is visible the moment you glance at your open tabs. A "Stop alarm" button appears the moment it starts ringing, and it quiets itself on its own after two minutes if nobody's there to press it.
If the run actually finished while you were away for a while, the timer doesn't pretend it just happened — it reports that it's done and roughly how long ago, and it deliberately stays quiet rather than ringing an alarm for something that ended minutes earlier. You get an honest answer either way, without a false sense of urgency attached to a stale event.
Pause, resume and add a minute
Pause freezes the remaining time exactly where it stood; resume picks up from there rather than restarting the whole length. "+1 minute" extends whichever run is currently active — running or paused — for the common case where a task simply needs a little longer, without resetting your progress. Reset returns to the same configured length so you can run it again from the top, and nothing here is saved beyond the page: closing the tab or reloading it clears the run, on the view that a countdown reporting it finished days ago would read as a bug rather than a feature.
Questions
- Does an online timer work if I switch tabs?
- Yes, and this one is built specifically around that case. A browser throttles a background tab's timers hard — often to once a second, and sometimes suspended entirely for minutes on a locked phone or a laptop that went to sleep — so a timer that just counts down tick by tick drifts late exactly when you've switched away, which for a timer is the normal case rather than an edge case. This tool never counts down: the moment you press Start it records the exact clock time the run should finish at, and every time it needs to show you the remaining time, it recalculates from that fixed target against the current time rather than from how many ticks it managed to run. Switch to another tab for the full 10 minutes of a 10-minute timer, come back, and it will already show finished — not 9:58 because a couple of ticks got dropped.
- What happens if the timer finishes while I'm not looking at the tab?
- It tells you honestly rather than pretending nothing happened. If the run reached zero a long time before you came back, the banner reports that it's finished and roughly how long ago — "Finished 6 minutes ago", for instance — instead of ringing the alarm as though it just happened at the moment you returned. If you were only away briefly and the tab noticed within a few seconds of the real end time, the alarm rings normally. Either way the browser tab's title updates to show the countdown or the finished state, which is the one signal that actually reaches you while you're working in a different tab — a toast notification inside a tab you've switched away from is not.
- Does the alarm sound need me to download anything?
- No. The tone is generated in your browser using the Web Audio API — the same technology a synthesiser or a drum machine plugin uses — rather than an audio file being fetched from a server. Nothing about this tool makes a network request at any point, which is also why the alarm keeps working with no internet connection at all once the page has loaded. Starting the timer is what unlocks audio playback in the browser (autoplay rules require a click somewhere before a page can play sound), which is also why there's no separate "enable sound" step to remember.
- How do I stop the alarm once it starts ringing?
- A "Stop alarm" button appears the moment it starts, right where your eyes already are because it sits beside the big finished readout. Clicking it silences the tone immediately without resetting anything else — the finished state and the elapsed time it reports stay exactly as they were. If nobody stops it, the alarm quiets itself automatically after two minutes rather than ringing indefinitely into an empty room.
- Can I add more time without starting over?
- Yes — the "+1 minute" button works whether the timer is running or paused, and it extends the current run rather than resetting it. That's the common case when a task is running slightly long: a talk that needs another minute, water that isn't quite boiling yet, a break that's worth stretching. Reset is the separate control for genuinely starting over at the same configured length, and "Set a new time" from the finished screen takes you back to picking a fresh duration.
- Why is there no 2-minute or 25-minute preset?
- The nine presets here — 1, 3, 5, 10, 15, 20, 30, 45 and 60 minutes — are the lengths people actually reach for as a plain countdown: tea, a plank hold, a warm-up, a study block, a nap. A 25-minute focus block with automatic breaks and a running session tally is a different tool with a different job — this site's Pomodoro Timer covers that specifically, and linking the two would just duplicate one of them badly. Any other length is one tap away through the hours/minutes/seconds entry next to the presets, so nothing here is actually unreachable.