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About this date difference calculator
How many days until a deadline, a holiday or a contract renewal? How long ago did a project start? Counting on a calendar is slow and error-prone, especially across months of different lengths and leap years. This date difference calculator gives you the exact number of days between two dates, the same span in weeks and in years-months-days, and the number of business days.
Business days count Monday to Friday only. Public holidays vary by country and are not subtracted, so adjust manually for local holidays. Calculations are done in UTC to avoid the classic one-day error around daylight-saving time changes. Use "Include end date" when both the first and last day should count, such as for hotel nights versus event days or leave requests.
Typical uses include counting days left until a visa expires, calculating notice periods and probation periods, working out how many days an invoice is overdue, planning a countdown for a launch or wedding, and checking the length of a rental or subscription term. Project managers often need business days rather than calendar days when estimating delivery, so both are shown side by side. For legal or financial deadlines, always confirm the counting rule in the contract, because some agreements exclude the first day, some include both ends, and some roll a weekend deadline forward to the next working day.
How to use it
- Choose a start date and an end date (the order does not matter).
- Tick Include end date if the last day should be counted.
- Read the totals in days, weeks, months and business days.
FAQ
Does it handle leap years?
Yes. Real calendar dates are used, so 29 February is counted when it exists.
Why are business days different from my HR system?
This tool does not know your public holidays. Subtract them manually.
Can I count backwards?
Yes; if the end date is before the start date the dates are swapped automatically.
Is it free?
Yes, free and runs locally.