OneTaskBy Tim King · Updated
Countdown Timer to Any Date
Named Event Countdown With Total Hours and Seconds Left, Updating Each Second
OneTask is free, with no sign-up, and built by one person.
If this tool saved you time, a coffee helps keep new ones coming.
How the Countdown Timer works
This countdown timer ticks down live to any date and time you set, showing days, hours, minutes and seconds. Give the event a name and the countdown carries it, whether it is a wedding, a holiday, an exam or a launch. It uses your device's clock and time zone.
How the countdown timer works
The formula subtracts the current moment from the target moment and splits the gap into whole days, then the hours, minutes and seconds left over. The page recalculates every second, so the display keeps ticking without a refresh.
Worked examples
For example, from 9:00 on 30 September 2026 to 14:00 on 12 June 2027 is 255 days and 5 hours, or 6,125 hours in total. As a second example, a countdown of exactly 100 days holds 2,400 hours and 8,640,000 seconds.
Time zones and clock changes
The target time is read in your device's local time zone. If a daylight saving change falls before the event, the total hours shift by one, but the event still arrives at the local time you entered.
How many seconds are in a countdown?
Multiply days by 86,400, hours by 3,600 and minutes by 60, then add them. The table converts a range of countdown lengths into hours and seconds.
Countdown lengths in days converted to hours, minutes and seconds
| Days | Hours | Minutes | Seconds |
|---|---|---|---|
| 1 | 24 | 1,440 | 86,400 |
| 2 | 48 | 2,880 | 172,800 |
| 3 | 72 | 4,320 | 259,200 |
| 5 | 120 | 7,200 | 432,000 |
| 7 | 168 | 10,080 | 604,800 |
| 10 | 240 | 14,400 | 864,000 |
| 14 | 336 | 20,160 | 1,209,600 |
| 21 | 504 | 30,240 | 1,814,400 |
| 30 | 720 | 43,200 | 2,592,000 |
| 50 | 1,200 | 72,000 | 4,320,000 |
| 60 | 1,440 | 86,400 | 5,184,000 |
| 90 | 2,160 | 129,600 | 7,776,000 |
| 100 | 2,400 | 144,000 | 8,640,000 |
| 120 | 2,880 | 172,800 | 10,368,000 |
| 180 | 4,320 | 259,200 | 15,552,000 |
| 200 | 4,800 | 288,000 | 17,280,000 |
| 250 | 6,000 | 360,000 | 21,600,000 |
| 300 | 7,200 | 432,000 | 25,920,000 |
| 365 | 8,760 | 525,600 | 31,536,000 |
| 500 | 12,000 | 720,000 | 43,200,000 |
| 1,000 | 24,000 | 1,440,000 | 86,400,000 |
FAQ
What happens when the countdown reaches zero?
The timer shows that the event has started, and it stays that way. To count to a new event, change the date, time or name, and the countdown starts again from the new target straight away.
Does the countdown keep running if I close the page?
No timer runs in the background, but none needs to. The countdown is worked out from the clock each second, so when you open the page again it shows the correct time left immediately.
Can I count down to a time today?
Yes. Set today's date and a later time, and the countdown shows hours, minutes and seconds with zero days. It works well for a meeting, a deadline, a flight or the end of the working day.
See also: all Countdowns tools, Calendars, Durations, Work and Contracts, Date Formats, Time Zones and Travel, Sun and Daylight.
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