Date Duration and Business Days Calculator
Count total days between two dates, business days excluding weekends, and optionally US federal holidays. Both endpoint dates are included.
Last updated: October 2026
Your date range
How date duration is counted
This calculator uses inclusive counting: both the start date and the end date count as full days. January 1 to January 31 is 31 days, not 30. Inclusive counting matches how rentals, project plans, and subscription periods are normally quoted ("a 7-day rental" runs Monday through Sunday). If you need the exclusive difference, subtract one from the total, or set the end date a day later.
Business days are found by walking every date in the range and keeping the ones that survive your filters: drop Saturdays and Sundays when weekends are excluded, and drop dates on the federal holiday list when holidays are excluded. A holiday that lands on a weekend costs you nothing extra, because the weekend filter already removed it.
US federal holidays 2026
When a federal holiday falls on a Saturday, it is observed on the preceding Friday; when it falls on a Sunday, it is observed on the following Monday. Independence Day 2026 falls on a Saturday, so it is observed Friday, July 3. The built-in list used by the holiday toggle:
| Holiday | 2026 date | Weekday |
|---|---|---|
| New Year's Day | January 1 | Thursday |
| Martin Luther King Jr. Day | January 19 | Monday |
| Presidents' Day | February 16 | Monday |
| Memorial Day | May 25 | Monday |
| Juneteenth | June 19 | Friday |
| Independence Day (observed) | July 3 | Friday |
| Labor Day | September 7 | Monday |
| Columbus Day | October 12 | Monday |
| Veterans Day | November 11 | Wednesday |
| Thanksgiving | November 26 | Thursday |
| Christmas | December 25 | Friday |
Worked example
Take January 1 to January 31, 2026 with weekends excluded:
- Total days: 31 (both endpoints included)
- Weekend days: Saturdays and Sundays fall on Jan 3-4, 10-11, 17-18, 24-25, and 31, which is 9 days
- Business days: 31 - 9 = 22
- Calendar weeks: 31 / 7 = 4.43
Turn on the federal-holiday toggle and January 1 (New Year's Day, Thursday) and January 19 (MLK Day, Monday) are removed as well, leaving 20 business days. You can verify the weekend count on any calendar: January 2026 starts on a Thursday, so the month contains five each of Thursday, Friday, and Saturday, and four each of Sunday through Wednesday.
Common uses
Project planning. Enter kickoff and deadline, exclude weekends and holidays, and the business-day count is the real capacity your team has. Divide story points or deliverables by that number for the required daily pace.
Leave and notice periods. "Two weeks notice" is 10 business days, and many PTO policies accrue per pay period against business days. Counting both endpoints avoids the classic off-by-one that shortchanges a final paycheck.
Contract and SLA deadlines. Service agreements quoted in "business days" exclude weekends and often holidays. Run the range through both toggles to see the actual calendar date a 5-business-day SLA lands on.
Freelance billing. Day-rate contractors multiply the business-day count by their rate for fixed-scope quotes. The holiday toggle keeps the quote honest in December and around Thanksgiving.
Tenure and waiting periods. HR teams sometimes need exact tenure for probation periods and vesting schedules: 90 days from a start date is not the same as three months, and the inclusive count settles the boundary. The same math answers "how many days until" questions for product launches, visa timelines, and subscription renewals, where being off by one day can mean a missed deadline.
Date duration FAQs
How many business days are between two dates?
Enter the start and end dates above with Exclude weekends checked. The calculator walks each date in the range and counts days that are not Saturday or Sunday. For example, January 1 to January 31, 2026 contains 31 days, of which 22 are weekdays.
Does the calculator count the start and end dates themselves?
Yes, both endpoints are included. January 1 to January 31 is 31 days, not 30. This inclusive convention matches how most project plans and rental periods count days. If you need exclusive counting, set the end date one day later and subtract one.
Which US federal holidays are excluded?
The built-in 2026 list covers New Year's Day (Jan 1), Martin Luther King Jr. Day (Jan 19), Presidents' Day (Feb 16), Memorial Day (May 25), Juneteenth (Jun 19), Independence Day observed (Jul 3), Labor Day (Sep 7), Columbus Day (Oct 12), Veterans Day (Nov 11), Thanksgiving (Nov 26), and Christmas (Dec 25). When a holiday falls on a weekend it is observed on the adjacent weekday, following the federal observed-day rule.
What is the difference between business days and work days?
They usually mean the same thing: Monday through Friday excluding public holidays. Some industries use different conventions, for example finance counts settlement days under its own holiday calendar, and Middle Eastern work weeks often run Sunday through Thursday. This calculator uses the standard US Monday-to-Friday business week.
How do I count only weekdays without holidays?
Check Exclude weekends and leave the federal holidays box unchecked. The result is the number of Monday-to-Friday days in the range, which is what most people mean by business days when no holiday calendar applies.
Can I use this for project timelines?
Yes, that is the most common use. Enter the project start and deadline, exclude weekends and holidays, and the business-day count tells you how many working days the team actually has. Divide the remaining work by that number to get the required daily pace.
Is my data sent anywhere?
No. The date math runs entirely in your browser with JavaScript. Nothing you enter leaves your device.