Business Days Calculator (Add, Subtract & Count Work Days)
Count working days between dates or add business days to a starting date with custom weekend and holiday exclusions.
Privacy First: 100% Client-Side Processing
Processed in your browser. Files are never uploaded.
How to Use the Business Days Calculator (Working Days & Holiday Exclusion)
- 1Select your calculation mode: count work days between two dates, or add/subtract business days from a start date.
- 2Input the start date and the end date or number of business days.
- 3Check or uncheck Saturday/Sunday as weekend days based on your work schedule.
- 4Toggle whether to automatically exclude official US Federal holidays.
- 5View the exact business day count, total elapsed calendar days, weekend days, and excluded holidays.
Formula & How It Works
Workday Enumeration & Holiday Calendar Logic
Iterates through calendar dates checking weekday indices against designated weekend masks and checking holiday dates matching floating federal observances (e.g., Memorial Day, Labor Day, Thanksgiving).
Worked Examples
Standard 2-Week Sprint
Input: Monday Oct 5, 2026 to Friday Oct 16, 2026 (Mon-Fri workweek)
Explanation: Two standard 5-day workweeks total exactly 10 business days.
Adding 30 Business Days to Project Start
Input: Start Nov 2, 2026 + 30 Business Days (Excluding US Thanksgiving)
Explanation: Accounts for 6 weekends and the Thanksgiving federal holiday to identify the exact 30th working day.
Contract Turnaround Across New Year
Input: Dec 24, 2026 to Jan 4, 2027
Explanation: Excludes 4 weekend days plus 2 non-weekend federal public holidays.
Frequently Asked Questions
How many business days are in a typical year?▼
A standard year with Monday-to-Friday workweeks has 260 or 261 weekdays. After subtracting 10 to 11 official US Federal holidays, there are typically 250 to 252 business days.
Which US Federal holidays are included?▼
New Year's Day, Martin Luther King Jr. Day, Washington's Birthday (Presidents' Day), Memorial Day, Juneteenth, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day, and Christmas Day.
What happens when a federal holiday falls on a weekend?▼
Under US Federal law (5 U.S.C. 6103), if a holiday falls on Saturday, it is legally observed on the preceding Friday. If it falls on Sunday, it is legally observed on the following Monday.
Can I count business days with Saturday as a working day?▼
Yes. This calculator allows you to toggle Saturday or Sunday independently to support 6-day workweeks common in retail, construction, and logistics.
Does the start date count as day one?▼
You can choose inclusive or exclusive counting. In standard business contracts, the start date is day zero (action begins next day), meaning 1 business day from Monday is Tuesday.
Does this tool store my dates?▼
No. All calculations run strictly in your web browser. No dates, schedules, or locations are ever uploaded or transmitted.
Quick Reference & Conversion Table
| Start Date | End Date | Total Calendar Days | Weekend Days | Net Business Days |
|---|---|---|---|---|
| Monday | Friday (Same Week) | 5 Days | 0 Days | 5 Business Days |
| Monday | Monday (Next Week) | 8 Days | 2 Days | 6 Business Days |
| Friday | Monday (Next Week) | 4 Days | 2 Days | 2 Business Days |
| 1st of Month | End of 30-Day Month | 30 Days | 8–9 Days | 21–22 Business Days |
| Annual Span | Full 365 Days | 365 Days | 104 Days | 250–252 Business Days |
⚠️ Common Pitfalls to Avoid
- •Assuming business days simply equals calendar days multiplied by 5/7, which fails on short spans and ignores public holidays.
- •Forgetting observed holiday rules when a federal holiday falls on a Saturday (observed Friday) or Sunday (observed Monday).
- •Overlooking regional, provincial, or bank-specific closure days not recognized as statutory federal holidays.
💡 Practical Real-World Uses
- •Calculating legal turnaround timelines for court filings and formal notices.
- •Projecting project management sprints, construction milestones, and sprint deliverable schedules.
- •Verifying banking settlement timeframes (ACH, wire transfers, and escrow clearance).
Calendar Days vs Business Days
| Factor | Calendar Days | Business Days |
|---|---|---|
| Includes Weekends | Yes, counts all 7 days of the week | No, excludes Saturday and Sunday (or custom) |
| Includes Holidays | Yes, counts continuous clock time | No, excludes bank and statutory public holidays |
| Typical Legal Standard | Contract cure periods, lease expiration notices | Court discovery deadlines, securities clearing (T+1) |
| Annual Count | 365 or 366 days | Typically 250 to 252 days |
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