How to use it
- Start date — defaults to today, so the result works as a countdown.
- End date — the later date. If you enter an earlier one, the dates are swapped and the result tells you so.
- Include the end date — tick this when both the first and last day should count as full days.
Should you include the end date?
By default the calculator counts the days from the start to the end — the number of midnights crossed. Monday to Tuesday is 1 day. That's the right count for "how many days until", for ages and for interest periods. Ticking the box adds exactly one day, which is what you want when the last day is used in full, such as a run of vacation days or a multi-day event.
| Question | Include end date? | Example |
|---|---|---|
| How many days until my trip? | No | Oct 8 → Oct 20 = 12 days |
| How many nights is a hotel stay? | No | Check in Jul 3, check out Jul 7 = 4 nights |
| How many vacation days does June 1–7 use? | Yes | 7 days |
| How long is a Friday-to-Sunday festival? | Yes | 3 days |
How the count works
Each date is treated as midnight at the start of that day, and the difference is measured in whole days. Because all dates are handled in UTC, a daylight saving change never creates a 23- or 25-hour day, and leap days (February 29 in 2024, 2028, 2032…) are counted automatically.
The years-months-days line counts whole calendar months first, then the leftover days. When the start date is the 29th, 30th or 31st and a month is too short, that month is completed on its last day — so January 31 to February 29, 2024 is exactly 1 month. This matches how the date calculator adds months, so the two tools always agree.
Worked example
From January 1, 2026 to December 31, 2026:
- Without the end date: 364 days — exactly 52 weeks — of which 260 are business days.
- With the end date: 365 days, the whole year: 52 weeks and 1 day. Business days rise to 261, because December 31, 2026 is a Thursday.
Business days and holidays
The business-day count includes Monday through Friday among the days counted and leaves out Saturdays and Sundays. It does not subtract public holidays, because they differ by country, state and employer. For U.S. federal working days, subtract the federal holidays that fall on weekdays in your range — there are 11 a year: New Year's Day, Martin Luther King Jr. Day, Presidents' Day, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving and Christmas. When a fixed-date holiday falls on a weekend, it is usually observed on the nearest Friday or Monday.
Counting dates by hand
January, March, May, July, August, October and December have 31 days; April, June, September and November have 30; February has 28, or 29 in a leap year. A common year is 52 weeks and 1 day, and a leap year is 52 weeks and 2 days — which is why a date's weekday moves forward by one each year, or by two after a February 29.
Frequently asked questions
How do I count the days between two dates?
Enter both dates above. By hand, count the days remaining in the start month, add the full months in between, then add the day of the month of the end date. From March 20 to May 5 that is 11 + 30 + 5 = 46 days.
Does the calculator count leap years?
Yes. Every February 29 inside the range is counted, so a span that includes one is a day longer than the same span in other years.
What counts as a business day?
Monday through Friday. Weekends are excluded, but public holidays are not, since they vary by location and employer. Subtract any holidays that fall on weekdays in your range.
How do I find how many days until a date?
Leave the start date as today and enter the target date as the end date. For holidays, our countdowns such as days until Christmas do it automatically.
How many weeks are between two dates?
Divide the number of days by 7. The calculator shows both whole weeks plus leftover days and the exact decimal number of weeks.
Last updated: October 8, 2026