About this date calculator
Count the days between two dates, or move a date forwards and backwards by years, months, weeks and days. The result is broken down into every unit, from years down to seconds.
What people use it for
- Days left until a deadline, exam or trip.
- Your exact age in years, months, days — or seconds.
- The end date of a notice period, contract or training plan.
- How long ago something happened.
- Which weekday a future date falls on.
Should I count the end day?
Tick the box when both the first and last day count, as with a holiday booking or a stay. Leave it clear when you want the gap between the dates, as with a countdown.
How are months counted?
Adding a month moves to the same day number in the next month. Where that day does not exist, the result lands on the last day of that month — 31 January plus one month gives 28 February.
Does it handle leap years?
Yes. Every calculation uses the real calendar, so 29 February and leap years are counted correctly.