Date & Time
Days between dates, deadlines, time zones and timestamps, worked out from your browser's own calendar. 8 free tools.
- Date Difference CalculatorDays, weeks and months between two dates.
- Add or Subtract DaysFind the date N days before or after another, optionally weekdays only.
- Countdown TimerA live countdown to any date and time.
- Stopwatch & TimerStopwatch with laps and a timer with an alarm.
- Time Zone ConverterConvert a time between any two zones, daylight saving included.
- Unix Timestamp ConverterEpoch seconds or milliseconds to a readable date, and back.
- Working Days CalculatorBusiness days between two dates, minus weekends and holidays.
- Week Number FinderISO week number for any date, and the dates in that week.
Before you use them
Notes on date and time tools
Calendar rules the date tools follow
Counting days: ends included or not
From 1 March to 3 March is 2 days by subtraction, but 3 days if you count both the first and last day, as hotel stays and leave forms sometimes do. The Date Difference Calculator shows the plain difference and has a switch to include the end date.
Leap years
A year is a leap year if it divides by 4, except century years, which must also divide by 400. So 2000 was a leap year and 2100 will not be. All the date tools use the browser's built-in Gregorian calendar, which applies this rule.
ISO week numbers
Under ISO 8601, weeks start on Monday and week 1 is the week containing the year's first Thursday. That means 29 December can belong to week 1 of the next year, and 1 January can fall in week 52 or 53. The Week Number Finder shows the ISO year next to the week for this reason.
Timestamps and time zones
| Fact | Value |
|---|---|
| Unix time starts at | 1 Jan 1970 00:00:00 UTC |
| Seconds timestamp today has | 10 digits |
| JavaScript / milliseconds timestamp has | 13 digits |
| Signed 32-bit seconds run out at | 19 Jan 2038 03:14:07 UTC |
The Time Zone Converter uses the IANA time zone database built into your browser, so daylight saving changes are applied for the date you pick, not just today's offset.