Days Between Dates Calculator

How do I calculate days between dates?

1. Choose a start date and an end date, or use Today next to either field.
2. Leave the counting option off for the standard date difference. Turn it on to count both dates.
3. Calculate, review the number of days and whole weeks, then copy the summary.

What does “include both dates” mean?

The standard difference counts calendar-day boundaries. July 1 to July 2 is 1 day. Including both dates counts July 1 and July 2, giving 2 days. For the same date, the standard result is 0 days; including that date gives 1 day.

Do daylight saving time or time zones change the result?

No. This tool compares date-only values without a time zone or time of day. It counts calendar days, not elapsed 24-hour periods. Consecutive dates are 1 day apart even when local clocks change and midnight-to-midnight lasts 23 or 25 hours. Today is the only feature that reads your device’s local date.

Are leap years included?

Yes. Gregorian leap years are divisible by 4, except century years that are not divisible by 400. The year 2000 is a leap year; 1900 is not. February 28 to March 1 is 2 days in 2024 and 1 day in 2025, before adding an optional endpoint day.

What if I put the dates in reverse order?

Reversed dates are accepted. The tool shows a positive distance and explicitly says when the end date is earlier. Swap dates reverses the fields. The option to include both dates still adds 1; it does not create a negative duration.

What do whole weeks and remaining days mean?

The selected day count is divided into complete groups of 7 and the leftover days. For example, 10 days is 1 whole week and 3 days. This is not a count of named calendar weeks. No months or years are approximated, and weekends and holidays are included.

Which calendar is used for historical dates?

All supported dates use the proleptic Gregorian calendar: modern Gregorian rules extended back to year 0001. The calculation does not reproduce regional calendar changes, skipped historical dates or the Julian calendar. Year 0000, BCE dates, impossible dates and years after 9999 are not supported.

Why are dates displayed differently from the summary?

Your browser’s date picker may show a local date format. The summary always uses YYYY-MM-DD to make the year, month and day unambiguous. All three parts are required. Dates are checked before calculation rather than silently rolling an invalid date into the next month.