100-Day Calculator
Calculate the exact date 100 days from any start date. Find milestones, weekday, weekly breakdown, and monthly distribution.
Business Days Between Dates Calculator
Count the number of business days (weekdays) between two dates. Excludes weekends automatically for accurate working day calculations.
Start Date
End Date
Business Days⧉
20
Calendar Days⧉
27
Weekend Days⧉
7
Planning notes, formulas, and examples
About the Business Days Between Dates Calculator
The Business Days Between Dates Calculator counts the number of weekdays (Monday through Friday) between any two dates. Unlike a simple day counter, this page excludes Saturdays and Sundays, giving you the actual number of working days in a given period.
Business day calculations are critical in many professional contexts. Legal deadlines often reference business days rather than calendar days. Shipping estimates, project timelines, contract terms, and payroll periods all rely on accurate business day counts.
The calculator uses day-of-week algorithms to determine which days fall on weekends and excludes them from the count. It handles any date range, from a few days to many years, and does not exclude public holidays because those vary by country and jurisdiction.
When This Page Helps
Legal deadlines, delivery estimates, and project timelines often use business days rather than calendar days. This calculator shows the weekday count between any two dates without manual calendar counting. It's useful for lawyers, project managers, HR professionals, and logistics planners.
How to Use the Inputs
- Enter the start date with year, month, and day.
- Enter the end date with year, month, and day.
- The calculator displays the number of business days (Mon–Fri).
- Weekend days are automatically excluded from the count.
- Note: public holidays are not excluded as they vary by location.
- View the total calendar days and weekend days for comparison.
Formula used
For each day from start to end:
1. Calculate day of week using Zeller's congruence
2. Count the day if it falls on Monday through Friday
3. Skip Saturdays (6) and Sundays (0)
Efficient formula: Business Days = Total Days − 2 × floor(Total Days / 7) − adjustments for partial weeks.Example Calculation
Result: 20 business days
February 2026 starts on a Sunday. From Feb 1 to Feb 28, there are 27 calendar days. Removing 8 weekend days (4 Saturdays and 4 Sundays) leaves 20 business days, which is a typical work month.
Tips & Best Practices
- A standard month has approximately 20–23 business days.
- A typical year has about 260 business days (52 weeks × 5 days).
- For legal deadlines, confirm whether holidays should also be excluded.
- Most shipping estimates use business days, not calendar days.
- To include the end date in the count, add 1 to the result.
- HR departments use business day counts for PTO accrual calculations.
Business Days in Professional Contexts
Business day counting is fundamental to commerce, law, and project management. Shipping companies promise deliveries in business days. Banks process transactions on business days. Courts set deadlines in business days. Understanding the distinction between calendar and business days prevents costly errors.
Estimating Business Days
For quick estimates: each full week contains 5 business days, each month averages about 21.7 business days, and each year averages about 261 business days. These approximations are useful for rough planning but should be verified with exact calculations for critical deadlines.
Holiday Considerations
Public holidays remove additional days from the business day count. The US observes 11 federal holidays, the UK has 8 bank holidays, and other countries have varying numbers. Always check the applicable holiday schedule for your jurisdiction.
Sources & Methodology
Last updated:
Frequently Asked Questions
A business day is any day from Monday through Friday that is not a public holiday. This calculator counts weekdays only. Public holidays vary by country and are not automatically excluded—you may need to subtract them manually.
No, this calculator excludes weekends (Saturday and Sunday) but not public holidays. Holiday schedules vary by country, state, and even company. You should manually subtract any holidays that fall on weekdays within your date range.
A typical year has about 260–262 business days (52 weeks × 5 days, plus 1–2 extra weekdays depending on which day January 1 falls). Subtracting public holidays, the US typically has about 250 working days per year.
Legal deadlines use business days because courts and government offices are closed on weekends. Filing deadlines, response periods, and statutory waiting periods are measured in business days to ensure all parties have equal access to working days for compliance.
By convention, this calculator counts business days between the two dates, not including the start date itself. If you need to include both endpoints, add 1 to the result (if the start date is a business day).
Some countries observe a Sunday–Thursday or Saturday–Wednesday work week. This calculator uses the international Monday–Friday standard. For alternative work weeks, you would need to adjust the excluded days accordingly.
More in this topic
120-Day Calculator
Calculate the exact date 120 days from any start date. Get milestones, weekday info, and monthly breakdown for 120-day planning periods.
180-Day Calculator
Calculate the exact date 180 days from any start date. Find the half-year mark with milestones, weekly breakdown, and monthly distribution.