Date Difference Calculator
Find the number of days, weeks, months and years between two dates, including business days.
Runs in your browser — your data never leaves your device.
About the Date Difference Calculator
How many days until an exam, between two invoices, or since a project started? Enter two dates to get the exact difference in days and in years, months and days — plus weeks, business days, weekend days, hours and minutes.
Use Include the end date when both the first and last day should count, for example when counting leave days or the length of an event.
How to use the Date Difference Calculator
- Enter the start date and end date.
- Tick Include the end date if the last day should be counted too.
- Press Calculate difference.
Formula
- Total days = End date − Start date (in calendar days)
- Including the end date adds one day.
- Business days count Monday to Friday only; public holidays are not removed.
- Years, months and days count whole calendar months first, then the remaining days, so different month lengths and leap years are handled correctly.
Examples
- 1 January 2026 → 31 December 2026 = 364 days (365 with the end date included).
- 1 March 2026 (Sunday) → 1 April 2026 = 31 days, of which 22 are business days.
Frequently asked questions
Should I include the end date?
Include it when counting a span where both days are used, such as leave from Monday to Friday (5 days). Leave it off to measure the time between two moments, such as days until a deadline.
Are public holidays excluded from business days?
No. Business days only exclude Saturdays and Sundays because holidays differ by country and organisation.
Can the end date be before the start date?
Yes. The calculator swaps the dates and tells you, so you still get the correct number of days.