Date Difference Calculator: Days Between Two Dates
This calculator counts the days, weeks, months and years between two dates, including or excluding the end date. It is the quick answer for project deadlines, notice periods, contract terms and countdowns.
Inclusive or exclusive counting
From 1 March to 10 March is nine days if you count the gap and ten days if you count both endpoints. Contracts, hotel stays and leave policies each follow their own convention, so state which one you are using. Hotel nights, for example, are always the exclusive count.
Working days versus calendar days
Business deadlines usually run on working days, which excludes weekends and public holidays. A 30 working day period spans about six calendar weeks, and public holidays vary by country and region — so a shared international deadline needs an agreed holiday calendar, not just a date count.
Common uses
- Project schedules and milestone tracking.
- Notice periods, probation periods and contract end dates.
- Interest and penalty calculations that accrue daily.
- Countdowns to travel, exams or launch dates.
Key takeaways — Date Difference Calculator
- Decide up front whether the end date is included.
- Distinguish calendar days from working days for legal and business deadlines.
- Time zones can shift a date boundary by a full day on international agreements.