Step-by-step guide: How to Count Days Between Two Dates (Including Working Days)
How to use the Date Difference Calculator
- Choose whether you want the time between two dates or a date a certain number of days away.
- For the difference, enter a start and end date. Tick Include the end date if both days should count, as in “from Monday to Friday inclusive”.
- To add or subtract, enter a start date and a number of days, and choose calendar days or business days.
- For business days, list any public holidays to skip, one date per line.
- Read the results: total days, the same period in weeks, months and years, and the number of business days.
Example: a 30-business-day deadline
A contract says a response is due within 30 business days of Monday 2 November 2026, and 26 November is a public holiday. Choosing Add, 30, Business days and listing 2026-11-26 as a holiday gives Tuesday 15 December 2026.
The count starts from the next business day, so 3 November is business day 1. Weekends and the listed holiday are skipped.
How days are counted
Dates are treated as whole calendar days in UTC, so daylight-saving changes never add or remove an hour that would distort the count. The difference between two dates is the number of midnights between them: from 1 March to 2 March is 1 day. Ticking “Include the end date” adds one, which is how inclusive periods such as hotel nights or leave days are often described.
The breakdown in years, months and days uses the same calendar-aware method as the Age Calculator. Business days count Monday to Friday and exclude any holidays you list; when adding business days, counting begins on the day after the start date.
Where accurate date counts matter
- Notice periods, contract terms and statutory deadlines.
- Project schedules and sprint planning.
- Shipping and delivery estimates in business days.
- Countdowns to events, exams and trips.
- Interest and billing periods measured in days.
Limitations to keep in mind
- Business days assume a Monday-to-Friday working week. Countries with a different weekend (such as Friday–Saturday) need manual adjustment.
- Public holidays are not built in, because they vary by country and region. Add the ones that apply.
- Legal deadlines may have specific counting rules (for example, excluding the day of service). Check the rule that applies to you.
How your data is handled
Everything is calculated in your browser; the dates you enter are not stored or sent.
Frequently asked questions
How many weeks are between two dates?
Divide the number of days by 7. The calculator shows the result as whole weeks and remaining days, for example “12 weeks and 3 days”.
Does the count include the start date?
By default, the count is the number of days from the start date to the end date, which does not count both ends. Tick “Include the end date” to count both.
Are leap years taken into account?
Yes. The calculator uses the real calendar, so 29 February is counted in leap years.