Date calculator
Add or take away days, weeks, months, years or working days. To count the days between two dates, use days between dates.
How the calculator counts
Days and weeks are counted exactly. The start date is not included, so 1 day after Monday is Tuesday, and 2 weeks after Wednesday 7 October is Wednesday 21 October.
Months and years keep the same day of the month. If that day does not exist in the target month, you get the month's last day. 31 January plus one month is 28 February, or the 29th in a leap year. 29 February 2028 plus one year is 28 February 2029.
Working days skip Saturdays, Sundays and bank holidays in England and Wales. This is the usual way to count notice periods, delivery estimates and many payment terms. Bank holidays in Scotland and Northern Ireland differ slightly; see UK bank holidays.
Common uses
- Deadlines: a 14-day cooling-off period, a 30-day return window or a 90-day notice period.
- Health: the 12-week point of a pregnancy or the date a course of treatment ends. For pregnancy, use the dedicated due date calculator.
- Planning: the date 6 months before a passport expires, or a project milestone 10 working days away.
For tables of common gaps, see weeks from today and days from today. To count only business days between two dates, use the working days calculator.
Frequently asked questions
What happens when I add a month to 31 January?
The result is the last day of February: 28 February, or 29 February in a leap year. When the target month is shorter, the calculator uses its last day rather than spilling into the next month.
What counts as a working day?
Monday to Friday, excluding bank holidays in England and Wales. Scotland and Northern Ireland have some different bank holidays.
Is the start date counted?
No. Adding 1 day to Monday gives Tuesday. This matches how deadlines such as "within 14 days" are normally counted. Check any contract or legal deadline against its own wording.