Count days between dates
Enter two dates, or a date and a number of days, get the answer instantly.
How many days are between two dates?
Subtract the earlier date from the later one, counting calendar days. From January 1 to December 25, 2026 there are 358 days — or 359 if you count both the first and the last day, as you would for the length of an event.
How do I count business days?
Count only Monday through Friday. From Friday, September 25 to Friday, October 2, 2026 there are 5 business days. Tick "without federal holidays" to also skip days like Columbus Day: from October 9 to October 16, 2026 that leaves 4.
What date is 90 days from a date?
Add the days one month at a time: 90 days after September 26, 2026 is Friday, December 25, 2026. Switch to "Add or subtract" and enter the days, weeks, months or years.
What happens when I add a month to January 31?
There is no February 31, so the date moves to the last day of February — February 28, 2026, or February 29 in a leap year. Months and years are added first, then weeks and days.
Which holidays does it skip?
The 11 US federal holidays: New Year's Day, Martin Luther King Jr. Day, Washington's Birthday, Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving and Christmas. A holiday on a Saturday is observed on the Friday before, one on a Sunday on the Monday after — July 4, 2026 is observed on Friday, July 3.
How many years, months and days are between two dates?
The calculator counts whole months first and then the days that remain. From Tuesday, March 17, 2026 to Tuesday, January 5, 2027 is 0 years, 9 months and 19 days, which is also 294 days in total.
Which years are leap years?
A year is a leap year if it is divisible by 4, except that century years must also be divisible by 400. So 2028 is a leap year, 1900 was not and 2000 was. February 29, 2028 plus one year lands on Wednesday, February 28, 2029, because 2029 has no February 29.
Three ways to measure the gap
A date difference can be expressed in total days, in weeks and days, or in years, months and days, and the three answers are different measures of the same gap. Total days is exact and unambiguous. Years-months-days depends on the length of the months in between, so the calculator adds whole months to the start date and counts the leftover days, the way ages and contract terms are usually stated. Business days count only Monday to Friday and, optionally, skip US federal holidays.
Worked example: March 17, 2026 to January 5, 2027
Counted as calendar days the gap is 294 days, or 295 if both the first and the last day are included. As years, months and days it is 0 years, 9 months and 19 days. It contains 210 business days (Monday to Friday, not counting the start date). Going the other way, 100 days after Tuesday, March 17, 2026 is Thursday, June 25, 2026. Adding one month to January 31, 2027 gives Sunday, February 28, 2027, and in the leap year 2028 it gives Tuesday, February 29, 2028.
Common mistakes
The classic one is the inclusive count: the days between Monday and Friday of the same week are 4, but a five-day event runs over 5 dates. Decide which meaning you need before you read the number. Adding months to a day near the end of a month is another, since the day is clipped to the month’s last day and subtracting the month back does not always return the original date. Finally, remember that business days here use US federal holidays only, so a company holiday, a bank holiday abroad or a regional observance is not excluded.
Sources: Gregorian leap-year rule — U.S. Naval Observatory and NIST time and frequency references; federal holidays — 5 U.S.C. § 6103 via the Office of Personnel Management. Related: days from today calculator, business days calculator, age calculator and day of the year calculator.