Working Days Calculator
Count the number of business days (Mon–Fri) between two dates — project deadlines, invoice due dates, vacation planning.
What is Working Days Calculator?
The working days calculator counts Monday–Friday business days between any two dates, optionally skipping the 11 U.S. federal holidays. Standard tool for setting contract deadlines, invoice due dates, project timelines, and PTO planning.
Formula
The calculator walks each day in the range and counts it unless:
- The day is a Saturday or Sunday
- The day is a U.S. federal holiday (when that option is enabled)
Federal holidays used: New Year's Day, MLK Day (3rd Mon Jan), Presidents' Day (3rd Mon Feb), Memorial Day (last Mon May), Juneteenth (Jun 19), Independence Day (Jul 4), Labor Day (1st Mon Sep), Columbus Day (2nd Mon Oct), Veterans Day (Nov 11), Thanksgiving (4th Thu Nov), Christmas (Dec 25). Weekend-falling holidays follow OPM observed-day rules.
Worked example
From January 1, 2026 to January 31, 2026 (inclusive, with U.S. holidays excluded):
- Total days: 31
- Weekend days: 9
- Holidays skipped: 2 (New Year's observed Jan 1, MLK Day Jan 19)
- Business days: 20
How to use this calculator
- Pick your start and end dates.
- Choose whether to count the end date itself (matters for contractual "within N business days" language).
- Turn U.S. federal holidays on if you need a strict count; leave off for a pure weekday count.
Frequently asked questions
Are state and religious holidays included?
No. Only the 11 U.S. federal holidays are supported. Add your own holidays (company-wide shutdowns, state holidays, Good Friday in some industries) manually by reducing the result.
What does "observed" mean for holidays on weekends?
Federal agencies follow OPM rules: a Saturday holiday is observed on the preceding Friday; a Sunday holiday is observed on the following Monday. This calculator applies the same rule.
Is Juneteenth always a federal holiday?
Yes — since June 17, 2021 (Juneteenth National Independence Day Act). The calculator includes it for every year starting 2021.
How many business days in a typical year?
About 251 to 253 for a typical U.S. federal calendar (365 or 366 days − 104 weekend days − 10 to 11 holidays that fall on a weekday).