Days between dates

Count the days from one date to another. See the same gap in weeks, months and years, and the business days in between.

By the Calcist team · Checked against known answers · Updated October 27, 2026

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Next: Want a date a number of days or business days from now? Use the date calculator. Working out someone's age? The age calculator adds the next birthday.

How the days are counted

Days = end date − start date
With the end date counted: days + 1

Each date is turned into a day number on the calendar (like Date.UTC in JavaScript), and the numbers are subtracted. That means a daylight saving change, when a day is only 23 hours long, never makes the count come out a day short.

By default the start date counts and the end date doesn't, like counting nights in a hotel: Monday to Friday is 4 days. Choose "Yes" under "Count the end date?" for things like the length of an event, where Monday to Friday is 5 days.

Worked example

From January 1 to December 31, 2026 is 364 days. Count the end date too and it's 365 days, the whole year. Of those 365 days, 261 are weekdays, and all 11 US federal holidays are observed on weekdays (July 4 is a Saturday, so it's observed on Friday, July 3), leaving 250 business days. Without the end date (364 days) it's 249, because Thursday, December 31 isn't counted.

Business days and holidays

Business days are Mondays to Fridays in the same span as the day count. With holidays on, these are skipped and listed by name, on the day the federal government observes them:

Holiday	Rule
New Year's Day	January 1
Birthday of Martin Luther King, Jr.	Third Monday in January (from 1986)
Washington's Birthday (Presidents Day)	Third Monday in February
Memorial Day	Last Monday in May
Juneteenth National Independence Day	June 19 (from 2021)
Independence Day	July 4
Labor Day	First Monday in September
Columbus Day	Second Monday in October
Veterans Day	November 11 (fourth Monday in October from 1971 to 1977)
Thanksgiving Day	Fourth Thursday in November
Christmas Day	December 25

A holiday on a Saturday is observed the Friday before; one on a Sunday, the Monday after. So when January 1 is a Saturday, the holiday is Friday, December 31.

Limitations

State holidays, Inauguration Day (only in the Washington, DC area), and company days off like the day after Thanksgiving aren't included.
Holidays are only applied from 1971, when the Monday holiday rules took effect.
Months and years in the breakdown use the month-end rule: one month after January 31 is the end of February.

Sources

U.S. Office of Personnel Management: Federal holidays (dates and the Saturday/Sunday "observed" rule)
5 U.S. Code § 6103 (the list of legal public holidays)
U.S. Naval Observatory: Introduction to calendars (Gregorian leap-year rule)

How we checked this

Before every update, this calculator is run in a real browser with these known answers, and it must match all of them:

Jan 1 to Dec 31, 2026: 364 days ✓
Including the end date: 365 days, 250 business days after 11 holidays ✓
Feb 1 to Mar 1, 2024 (leap year): 29 days ✓
Mar 1 to Apr 1, 2026 across the DST change: 31 days, not 30.96 ✓
November 2026: Veterans Day and Thanksgiving excluded, 19 business days ✓
Jan 1 to Dec 31, 2026 without the end date: 249 business days ✓
Reversed dates count from the end date ✓
Edge: same date with the end date counted is 1 day ✓
Jan 1 to Jul 1, 2024: 182 of 366 days = 0.497 years ✓
A full calendar year is 1.000 year, not 0.999 ✓

Last checked October 26, 2026. Spotted something wrong? The math is done in your browser with the formula shown on this page, so you can check any result by hand.

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Questions people ask

How many days are there between two dates?

Subtract the earlier date from the later one in calendar days. From January 1 to December 31, 2026 is 364 days, or 365 if you count the end date too.

Should I include the end date?

Leave it out to count nights or time passed (Monday to Friday is 4 days). Include it to count days of an event (Monday to Friday is 5 days).

How many business days are in 2026?

250, counting Monday to Friday from January 1 through December 31 (end date counted) and skipping the 11 US federal holidays, all of which are observed on weekdays in 2026. July 4 is a Saturday, so it's observed on Friday, July 3.

Does it handle leap years?

Yes. February 1 to March 1, 2024 is 29 days because 2024 is a leap year; in 2026 it's 28.

Which holidays are skipped?

The 11 US federal holidays, on their observed dates. Each one that falls in your range is listed by name under the result.

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