The online timer on this page is a countdown. You set hours, minutes, and seconds, press start, and the clock runs down to zero. At zero it plays three short beeps, if the tab is still open and the browser is allowed to make sound. The default is five minutes, because that is the search people type, but the fields accept anything from one second up to 24 hours. The fixed-length pages — one minute, five minutes, ten minutes, and the rest — open the same timer with that number already filled in.
A countdown is not a stopwatch. A stopwatch counts up and keeps laps. This timer counts down and then stops. If you need laps, the online stopwatch is a separate page, with Space to start and stop, L for a lap, and R to reset. A metronome is a repeating click at a tempo; it is not an alarm. The three tools stay apart so one page does not try to be a studio.
How to use the form: type hours, minutes, and seconds as whole numbers. Minutes and seconds have to sit between 0 and 59. An empty total is rejected, and so is anything past 24 hours. Start asks the browser to resume audio, because the later beeps come from that same audio context. Pause freezes the time that is left. Start again continues from that remainder, not from the preset, unless you press reset. Reset returns the page preset: five minutes on the main timer, or the length written in the URL on a minute page.
Fullscreen enlarges the digits on devices that allow it. A kitchen, a classroom, and a hall are easier to read from across the room as 05:00 than from a toolbar. If the browser blocks fullscreen, the countdown still runs in the page. The sound is three beeps, not a music file and not a voice. It will not fire if you close the tab, and a browser may silence a background tab. Leave this tab in front if the alarm is the point.
The minute pages are the same timer with a fixed start. 1 minute timer, 2 minute timer, 3 minute timer, 4 minute timer, 5 minute timer, 10 minute timer, 15 minute timer, 20 minute timer, 25 minute timer, 30 minute timer, 45 minute timer, 60 minute timer. Each one has the alarm, fullscreen, and pause. They do not share state: setting ten minutes does not change a five minute tab that is already running. That is deliberate. A link is a page, not an account.
The display uses minutes and seconds until the countdown reaches an hour, then it adds an hour digit. Five minutes opens as 05:00. Sixty minutes opens as 01:00:00. A fraction of a second still shows the second you are in, so the last moment reads 00:01 and then 00:00 rather than skipping the final second. Pause is a button, not a hidden gesture. Reset is explicit because a mis-tap should not throw away a twenty minute block you had already counted. Keyboard users can click the buttons; the stopwatch page is the one with Space, L, and R.
Nothing is uploaded and there is no account. The clock lives in the tab. Refresh and it is gone, including a paused remainder. Do not use a browser tab for anything whose safety depends on the alarm, such as an oven that can burn or a dose of medicine. Your phone has a clock that rings when the screen is locked. This page is for a countdown you are watching. The metronome stays the music tool if what you wanted was a beat rather than an ending.