TimerPlan15 Seconds timer
15 Seconds timer
0:00
Ends at —
Space starts and pauses · R resets
One thing a month worth timing
MonthlyOne thing a month worth measuring or capping with a clock — a payroll trap, a nap length, a meeting that never gets added up. Two sentences and the tool.
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What is a 15 seconds timer?
The Timerdial 15 seconds timer is a full countdown already set to 15 seconds: press start and it rings, keeps the screen awake, and shows the time left in the tab title. Fifteen seconds is the standard length of a short advertisement and of a mouthwash rinse, which is not a coincidence — it is about the longest a person will hold still for something without checking how much is left.
In other units that is 0:15 on a clock, 0.25 minutes, and 0.004167 of an hour, so 240 of them fit into an hour and 5760 into a day.
Because the finish is stored as an absolute clock time rather than counted in ticks, the countdown is exact after a spell in a background tab, and the alarm is booked into the audio clock the moment you press start — which is what lets it sound while the tab is frozen.
Press start, or press it after changing the length — this page is the ordinary timer with 15 seconds already in the box.
What people set 15 seconds for
a mouthwash rinse, a short social video, resting between heavy repetitions, a sprint interval. Fifteen seconds is the standard length of a short advertisement and of a mouthwash rinse, which is not a coincidence — it is about the longest a person will hold still for something without checking how much is left.
| In this unit | 15 seconds is |
|---|---|
| Seconds | %!d(float64=15) |
| Minutes | 0.25 |
| Hours | 0.004167 |
| On a clock | 0:15 |
| Written for the box | %!d(float64=15)s |
| Fits into an hour | 240 times |
| Fits into a day | 5760 times |
The address bar carries the length, so bookmarking this page keeps it, and adding ?auto=1 to the link starts the countdown as soon as it opens — useful on a shared screen where a click is one thing too many.
Next to it
Shorter: 10 seconds. Longer: 20 seconds.
Every length is listed on the timer by duration page. For a different kind of countdown, the countdown timer counts to a time of day instead of for a length, the kitchen timer runs several at once, and the pomodoro timer repeats work and break. To count upward instead, use the stopwatch.
Frequently asked questions
How long should I rinse with mouthwash?
Thirty seconds for most products and never less than fifteen, swished rather than held. The bottle usually says so in small print, and the reason people cut it short is that fifteen seconds without a clock feels like thirty.
How many seconds is 15 seconds?
%!d(float64=15) seconds, which is 0:15 on a clock and 0.25 minutes as a decimal. The timer accepts every one of those forms in its box — %!d(float64=15)s, %!d(float64=15), 0:15 — and they all set the same countdown.
Will a 15 seconds timer still ring if I switch tabs?
Yes. The alarm is scheduled into the audio clock at the moment you press start, so it sounds at the right time even if the tab has been frozen in the background since — unlike a page that only tries to make a sound once the time is up, by which point a throttled tab has already missed it. The remaining time is also written into the tab title and drawn into the tab icon, so you can read it without switching back.
How this works
Sources:
Reading a 15 seconds countdown
It is the same engine as every timer here. Absolute finish time, scheduled alarm, screen held awake — the only difference is that 15 seconds is already in the box.
The tab title carries it. So this page does not have to be the one you are looking at.
Nothing is stored. The length lives in the address bar, which is what makes a bookmark work.