Date calculator
Find out what the date will be in a number of days, weeks, months or years, or what it was that long ago.
Date calculator: what it is and how it works
Working out a future or past date is common when setting deadlines, payment due dates, delivery dates, warranty periods or the end date of a contract. This calculator adds or subtracts any combination of years, months, weeks and days to the date you choose and returns the resulting date and its weekday.
Years and months are applied first, then weeks and days. If the day does not exist in the target month, the last day of that month is used: for example, 31 January plus one month is 28 February (or 29 in leap years). Legal deadlines may be counted in working days; for those, use the working days calculator.
How to use it
- Choose the start date.
- Choose add or subtract and enter the years, months, weeks and days.
- Read the resulting date and the weekday.
End date = start date ± (years × 12 + months) months ± (weeks × 7 + days) daysWorked example
2 November 2026 plus 90 days is Sunday 31 January 2027. 31 January 2026 plus one month is 28 February 2026.
Frequently asked questions
What happens when adding a month to the 31st?
If the next month has no 31st, the result is its last day. So 31 March plus one month is 30 April.
Does it count working days?
No, it adds calendar days. To skip weekends and holidays, use the working days calculator.
Can I combine months and days?
Yes. Fill in years, months, weeks and days together; they are applied in that order.
Does it work for old or distant dates?
Yes, it works with any date in the Gregorian calendar.