Calculate differences between dates and determine age.

How Date Calculation Works
What is a Date Calculator?

A date calculator measures the distance between two points in time and states it in the units you need: whole days, hours, minutes and seconds, and a calendar breakdown in years, months and days.

The two readings answer different questions. Total days is a count. A calendar breakdown follows the calendar, where months have between 28 and 31 days, so the two cannot be derived from one another by division.

How to Use
  • Enter a start and an end date. The end date is filled with today, so a period up to now needs one field, and the result appears as you type.
  • Tick Include time on a field to work to the minute. Left unticked, a date is taken as midnight at the start of that day.
  • Today fills a field with the current date.
  • The format buttons change how figures and dates are written. They do not change the result.
  • Use Age instead to measure from a date of birth to right now.
What Gets Counted
DaysWhole days between the two moments, rounded down
DurationCalendar years, months and days, counted month by month
WeeksWhole seven day blocks in the period
Business daysMonday to Friday, both endpoints included, public holidays ignored
Important Notes
  • Everything is calculated in your own time zone, from the clock on this device. Two people in different zones can legitimately see a different result for the same input.
  • Daylight saving means some days are 23 or 25 hours long. The hour and minute counts follow the actual elapsed time, so they can differ from days multiplied by 24.
  • Business days count Monday to Friday only. No public holiday calendar is applied, because holidays differ by country and region.
  • Dates before 1582 are counted with today's calendar rules, which the Gregorian reform did not apply retroactively.
Privacy & Security: every calculation runs in your browser. No date you enter is sent anywhere, and the tool works with the network disconnected.