Work Days Calculator — Business Days Between Dates
Calculate business days between two dates or add business days to a date, excluding weekends and US holidays. See also Days Between Dates and Date Calculator.
Exclude US Holidays (optional)
How the Work Days Calculator Works
This calculator counts business days (Monday through Friday) between two dates, optionally excluding US federal holidays. It iterates through each day in the range, skipping Saturdays, Sundays, and any selected holidays. The "Add Business Days" mode counts forward from a start date, skipping non-business days until the specified number of working days has been reached.
Business Day Calculation Formula
Business Days = Calendar Days - Weekend Days - Holidays
Weekend Days per week = 2 (Saturday + Sunday)
Approximate: Business Days ≈ Calendar Days x (5/7)
Work Weeks = floor(Business Days / 5)
US Federal Holidays Reference
| Holiday | Date | Type |
|---|---|---|
| New Year's Day | January 1 | Fixed |
| Martin Luther King Jr. Day | 3rd Monday in January | Floating |
| Presidents' Day | 3rd Monday in February | Floating |
| Memorial Day | Last Monday in May | Floating |
| Independence Day | July 4 | Fixed |
| Labor Day | 1st Monday in September | Floating |
| Thanksgiving Day | 4th Thursday in November | Floating |
| Christmas Day | December 25 | Fixed |
When to Use This Calculator
Project management: Estimate delivery dates when requirements specify working days (e.g., "deliverable due in 45 business days").
Legal compliance: Calculate court filing deadlines, notice periods, and response windows that exclude weekends and holidays.
Shipping and logistics: Estimate package delivery dates based on carrier business-day processing and transit times.
HR and payroll: Determine pay periods, PTO accrual, and probation end dates based on working days.
Government processing: Passport renewals, permit applications, and tax filings often quote processing times in business days.
Solved Examples
Example 1: A project starts Monday, June 2, 2025 and needs 45 working days. When does it finish?
45 business days = 9 work weeks = 63 calendar days (9 x 7)
June 2 + 63 calendar days = August 4, 2025 (Monday)
Check for holidays: Independence Day (July 4) falls in this range, so add 1 more day.
Answer: August 5, 2025 (Tuesday), accounting for the July 4 holiday.
Example 2: How many business days between March 1 and March 31, 2025?
March 2025 has 31 days. Weekends: 5 Saturdays + 4 Sundays = 9 weekend days (Mar 1 is Saturday)
Business days: 31 - 9 = 22 (no federal holidays in March)
Answer: 21 business days between Mar 1 and Mar 31 (excluding start date).
Example 3: A legal notice requires 10 business days response time, served on Wednesday, November 26, 2025. Deadline?
Nov 27 (Thu, Thanksgiving) = holiday, Nov 28 (Fri) = business day 1
Count forward 10 business days, skipping weekends and Thanksgiving.
Answer: December 10, 2025 (Wednesday). The Thanksgiving holiday adds one extra calendar day.
Common Mistakes to Avoid
Using calendar days when the requirement says business days. 10 business days is about 14 calendar days, not 10. Missing this distinction can miss deadlines.
Forgetting holiday weekends. When a holiday falls on a Friday or Monday, it creates a 3-day weekend that reduces business days more than expected.
Counting the start date. Business day calculations typically start counting from the next day. A document served on Monday has Tuesday as business day 1.
Assuming the same holidays worldwide. US federal holidays differ from UK bank holidays, EU holidays, and other national calendars. Verify which holiday schedule applies.
Key Takeaways
- Business days = calendar days minus weekends minus holidays.
- A typical year has 261 business days (365 - 104 weekend days) before holiday deductions.
- After US federal holidays: approximately 253 working days per year.
- Quick estimate: multiply business days by 1.4 to get approximate calendar days.
- Start date is typically excluded from the count (day 1 is the next business day).
- For international projects, specify which country holiday calendar applies.
Frequently Asked Questions
What counts as a business day?
A business day (or working day) is any day from Monday through Friday that is not a public holiday. Saturdays and Sundays are always excluded from business day counts.
How many business days are in a year?
A typical year has approximately 261 business days (365 days minus 104 weekend days). After subtracting US federal holidays, it is approximately 253 working days. The exact number varies by year depending on how holidays fall.
Does this calculator account for holidays?
Yes. You can select which US federal holidays to exclude from the count. The calculator correctly handles both fixed-date holidays (like July 4) and floating holidays (like Thanksgiving, which is the 4th Thursday in November).
How do I calculate a deadline that is "10 business days" away?
Use the "Add Business Days to Date" mode. Enter today as the start date and 10 as the number of business days. The calculator will skip weekends and holidays to find the exact calendar date.
What about company-specific holidays?
This calculator includes the 8 major US federal holidays. If your company observes additional holidays (like the day after Thanksgiving or company-specific days), you may need to subtract those manually from the result.
How are holiday dates calculated for floating holidays?
Floating holidays are calculated using their official rules: MLK Day is the 3rd Monday in January, Presidents Day is the 3rd Monday in February, Memorial Day is the last Monday in May, Labor Day is the 1st Monday in September, and Thanksgiving is the 4th Thursday in November.
Is the start date included in the count?
No. The calculator counts days starting from the day after the start date. If you start on Monday and add 1 business day, the result is Tuesday. This matches the common interpretation of "within X business days."