Date Calculator
Count days, weeks, months and business days between two dates, or add and subtract days, weeks, months and years from a date.
About the Date Calculator
Count the exact time between two dates, including working days that skip weekends, or find the date a number of days, weeks, months or years before or after another date. Handy for deadlines, notice periods, contracts and trip planning.
How to use it
- Choose ‘Difference between dates’ or ‘Add / subtract’.
- Pick your dates or enter the amounts to add or subtract.
- Read the result in years, months and days, total days, weeks and business days.
How the count works
The difference is counted from the start date up to, but not including, the end date, which matches how spreadsheets and most contracts count elapsed time. From 1 January 2026 to 31 December 2026 is 364 days; tick ‘Include end date’ to count it as 365.
Business days count Mondays to Fridays only. The whole of 2026 contains 261 weekdays. Public holidays are not removed because they differ by country, so subtract them yourself for deadlines that depend on them.
Adding months and years
Months have different lengths, so adding one month to 31 January gives 28 February (or 29 in a leap year) rather than spilling into March. Years work the same way for 29 February. Weeks and days are then added on top. In business-day mode, weekends are skipped, so 5 business days after a Friday is the following Friday.
Everyday uses
Work out notice periods, visa and warranty expiry dates, project deadlines, the number of days until an exam or holiday, or how many working days you have to complete a task.
Frequently asked questions
Is the end date included?
By default the count excludes the end date, the same way most calculators and spreadsheets do. Tick ‘Include end date’ to add one day.
What counts as a business day?
Monday to Friday. Public holidays differ by country and are not removed.
What happens when I add a month to 31 January?
The date is clamped to the last day of the shorter month, so you get 28 or 29 February rather than skipping into March.