How to count the days between two dates
Pick a start date and an end date. The total is the number of days you move forward from the start to reach the end. From Monday to Wednesday is 2 days. This is the same as counting the start date but not the end date.
Tick Include the end date when both dates should count. A hotel stay counts nights, so leave it unticked. A holiday from 1 to 10 August covers 10 days, so tick it. With the box ticked, the end date counts as a full day in every result, including business days.
Worked example
From 15 January 2026 to 11 October 2026, not including the end date:
| Shown as | Result |
|---|---|
| Total days | 269 days |
| Weeks and days | 38 weeks, 3 days |
| Months and days | 8 months, 26 days |
| Years, months, days | 0 years, 8 months, 26 days |
| Business days (Mon–Fri) | 192 days |
Business days
Business days are the Mondays to Fridays in the range. Like the total, the count includes the start date and leaves out the end date unless you tick the box. Public holidays are not removed, because they differ by country, state and even employer. Subtract them yourself if your deadline depends on them.
In "Add or subtract" mode, adding business days skips Saturdays and Sundays. Adding 1 business day to a Friday gives the next Monday. Adding 1 business day to a Saturday also gives Monday.
Adding months and years
Months have 28 to 31 days, so adding a month moves to the same day number in the next month. If that day doesn't exist, the result is the last day of that month:
- 31 January + 1 month = 28 February (29 February in a leap year).
- 31 March + 1 month = 30 April.
- 29 February 2024 + 1 year = 28 February 2025.
Subtraction works the same way: 31 May − 3 months = 28 or 29 February. The tool tells you when a date was clamped. Spreadsheets do the same thing with EDATE.
Adding weeks is exact: 1 week is always 7 days.
Practical uses
- Invoice due dates: "Net 30" means 30 days after the invoice date. Add 30 days to find the due date, or let the invoice generator do it.
- Notice periods and contracts: a 3-month notice period from 30 November ends on 28 or 29 February, by the clamping rule above. Check your contract, as some define the period differently.
- Loan tenure: add the number of EMIs in months to the first EMI date to find the last one. The EMI calculator works out the payment.
- Age on a date: for a birthday-based age, the age calculator also shows the next birthday.
Accuracy
The calculator works with calendar dates only, so daylight saving changes and time zones can't add or lose a day. It uses the Gregorian calendar with the usual leap-year rule: every 4 years, except century years not divisible by 400. So 2000 was a leap year, and 2100 will not be.
Frequently asked questions
How many days are there between two dates?
What is 31 January plus one month?
Are public holidays excluded from business days?
How do I find a date 90 days from today?
Why does my answer differ from another calculator by one day?
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