How to Use This Calculator
1
Enter Start Date
Select or type the starting date for your calculation.
2
Enter End Date or Days
Choose an end date to count business days between them, or enter a number of business days to add/subtract.
3
Review Results
See the total business days, calendar days, weekends excluded, and any holidays in the range.
Key Terms
- Business Day
- A standard working day, typically Monday through Friday, excluding public holidays.
- Calendar Day
- Any day of the week including weekends and holidays.
- Federal Holiday
- One of 11 U.S. federal holidays when government offices and many businesses close.
- Lead Time
- The number of business days required to complete a task or deliver a product.
- SLA Window
- Service Level Agreement timeframe, often measured in business days rather than calendar days.
Real-World Examples
Example 1
Project Timeline
Start: March 10, End: April 18 (2025)
28 business days, 40 calendar days, 10 weekend days, 0 holidays.
Example 2
Shipping Estimate
Start: November 20, Add: 10 business days (2025)
End date: December 4. Skips Thanksgiving (Nov 27) and 4 weekend days.
Business Days per Month (2025, U.S.)
| Month | Calendar Days | Business Days | Federal Holidays |
|---|
| January | 31 | 21 | 2 (New Year's, MLK Day) |
| February | 28 | 19 | 1 (Presidents' Day) |
| July | 31 | 21 | 1 (Independence Day) |
| November | 30 | 19 | 2 (Veterans Day, Thanksgiving) |
| December | 31 | 22 | 1 (Christmas Day) |
Working with Business Days
Why Business Days Matter
Contracts, SLAs, legal deadlines, and shipping estimates all rely on business days. Misunderstanding business days vs. calendar days is one of the most common causes of missed deadlines. A '10-day delivery window' in business days is actually 14 calendar days — and can stretch to 16+ days around holiday weekends.
International Considerations
Business days vary by country. Many European countries observe more public holidays (10-15 per year) than the U.S. (11 federal). Some Middle Eastern countries use Sunday-Thursday as the work week. When working with international teams or clients, always specify the calendar standard being used.