Date calculator
Count the days between two dates, or find the date a number of days, weeks or months away.
Counting days the way calendars do
The calculator turns each date into a day count (days since a fixed starting day) using the Gregorian calendar’s leap-year rules, then subtracts. It never divides milliseconds, which is how many date tools end up a day out across a daylight-saving change.
“On a calendar” gives the same span in years, months and days, counting whole months from the start date: January 31 to March 1 is 1 month and 1 day. Business days are the weekdays in the span; US federal holidays can be left out as well, on the dates the federal government observes them.
Questions
Does “days between” count the first and last day?
By default it counts the first day but not the last, the way you’d say Monday to Friday is 4 days later. Tick “Include the end date” to count both, for example to count the days of a trip or an event that runs from one date to another inclusive.
What counts as a business day?
Monday to Friday. Tick “Leave out US federal holidays” to skip the 11 federal holidays too (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), on the days they are observed: a holiday on a Saturday is observed the Friday before, one on a Sunday the Monday after. State and bank holidays vary, so they aren’t included.
What happens when I add a month to January 31?
There’s no February 31, so the answer is the last day of February (28th, or 29th in a leap year). Adding months or years always keeps the day of the month when it exists and uses the month’s last day when it doesn’t, the same rule banks and most software use.
Are leap years and time zones handled?
Yes. The calculator counts calendar days with the Gregorian calendar’s leap-year rules (every 4 years, except century years not divisible by 400), and works with dates rather than clock times, so daylight-saving changes and time zones can’t add or lose a day.
How many days until Christmas?
The calculator opens on today and the next December 25, so the answer is right at the top. Change either date for any other countdown, such as a holiday, a due date or a deadline.
Is anything I enter saved or sent anywhere?
No. Every calculation happens in your browser. The dates appear in the page address only so you can bookmark or share the result.
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