How to calculate the days between two dates
Deadlines, notice periods, visa windows, and project plans all come down to one question: how many days apart are these two dates? A date calculator answers instantly and correctly — leap years, month lengths, and all.
Open the free date difference calculator →Free · no signup · no watermarks
Step by step
- Open the date difference calculator. Start the free calculator.
- Set the start date. Pick the first date — a contract signing, a booking, today.
- Set the end date. Pick the second date — the deadline, the return flight, the event.
- Read the difference. See the gap in days, plus weeks and months for planning conversations.
Tips that save a second try
- Decide whether your deadline counts the end date itself — 'within 30 days' often includes day 30, which changes the answer by one.
- For notice periods, count from the day after you give notice unless the contract says otherwise.
- Mentally sanity-check long spans with 'a year is 365 days, a month averages about 30' — if the result is far off, a date was mistyped.
Common questions
Does the calculation handle leap years?
Yes. The calculator uses real calendar math, so February 29, uneven month lengths, and year boundaries are all counted exactly — the places where counting on your fingers goes wrong.
Why do different tools sometimes disagree by one day?
It depends on whether the end date is included in the count. An exclusive count from Monday to Friday is 4 days; inclusive is 5. Check which convention your deadline uses and read the result accordingly.