Days Between Dates Calculator
Count the exact number of days between any two dates, with a weeks breakdown and an option to include the end date.
Pick a start date and an end date and get the exact day count between them — handy for deadlines, trip lengths, subscription windows, and project timelines. You can count both endpoints (the way people count vacation days) with one checkbox, and reversed dates simply show a negative difference.
How to use this calculator
- Pick the start date in the first field.
- Pick the end date in the second field.
- Optionally tick 'include the end date' if both the first and last day should count (trips, rentals, hotel stays).
- Press Calculate to see the total days, the full-weeks breakdown, and the signed difference.
The formula
Days between = end date − start date (in whole calendar days). With 'include end date': days between = end − start + 1.
Worked example
From January 1, 2026 to December 31, 2026 the calculator gives 364 days — exactly 52 weeks. Across February in leap year 2024 (February 1 to March 1) it gives 29 days, because February 29 is a real day on the calendar. Both results were verified against the calendar by hand.
Frequently Asked Questions
How does the calculator count the days?
It subtracts the two calendar dates, so the result is the number of midnights you cross between them — the same answer you get from date arithmetic in a spreadsheet. Moving from October 16 to October 20 is 4 days. If you tick 'include the end date', it adds one so both the first and last day are counted, which is how most people count a trip or a rental period.
What happens if the end date is before the start date?
You get a negative number, which is deliberate: it tells you the direction as well as the distance. The big 'days apart' figure stays positive for readability, and the signed difference (end minus start) shows the negative value, which is useful when chaining calculations.
Does it handle leap years correctly?
Yes. The count is computed from real calendar dates, so February 29 is counted in leap years: February 1 to March 1 is 29 days in 2024 and 28 days in 2025. There is no 30-day-month shortcut anywhere in the math.
How many days are there between January 1 and December 31, 2026?
364 days. A non-leap year like 2026 has 365 days in total, and the difference between its first and last day is one less, 364 — exactly 52 weeks. If you count both endpoints with the include-end-date option, you get the full 365.
Can I use this for a countdown to a birthday or deadline?
Yes — set the start date to today and the end date to your birthday, due date, or deadline, and the result is your day count. For a live ticking clock to a specific date and time, the Countdown Timer on this site does that job better.