CalcLabHQ

Business Days Calculator

Calculate the exact number of working days between two dates. Exclude weekends to plan project durations, leave, and invoices accurately.

Select Dates

Useful for leave applications where the first day counts as 1 day off.

Ready to Calculate

Select your start and end dates to count the number of working days and weekends between them.

Common Scenarios & Examples

Here are specific ways to use this tool:

HR & Leave How many vacation days am I using?

Enter your first day off and your last day off. Check "Include Start Date" to ensure the first day is counted as a vacation day.

Finance Invoice aging & late fees

Find out how many actual business days an invoice is overdue to calculate late penalties accurately, excluding weekends.

Project Sprint & Deadline Duration

Calculate the exact number of working days available in a sprint cycle (e.g., from Jan 1st to Jan 15th) to allocate tasks realistically.

Legal "10 Working Days" Notice

Verify if the time elapsed between a notice served and a deadline meets the legal requirement of business days.

Quick Reference: Business Days to Calendar Weeks

  • 5 Days = 1 Calendar Week
  • 10 Days = 2 Calendar Weeks
  • 20 Days ~1 Month (4 Weeks)
  • 60 Days ~3 Months (1 Quarter)
  • 250 Days ~1 Standard Work Year

How to Calculate Business Days Between Dates

Calculating the duration between two dates in "Working Days" is more complex than simple subtraction. It requires identifying the day of the week for every single day in the range and filtering out Saturdays and Sundays.

The Formula:
Total Days - (Saturdays + Sundays) = Business Days

However, nuances like whether to include the start date or end date can change the result by +/- 1 day. This calculator handles that logic instantly, making it a reliable Monday to Friday calculator.

Frequently Asked Questions

Why is "Include Start Date" important?

Standard date subtraction (End - Start) calculates the difference, effectively excluding the start day. However, if you are taking leave from Monday to Wednesday, you are absent for 3 days (Mon, Tue, Wed). Checking "Include Start Date" ensures that Monday is counted.

Does this account for public holidays?

No. This tool strictly removes weekends (Saturdays and Sundays). Because holidays vary wildly by state and country, you should calculate the total business days here and then manually subtract the number of holidays in that period.

What is the difference between calendar days and working days?

Calendar Days represent the total time elapsed on a clock (including weekends and holidays). Working Days represent the time available for productivity, usually Monday through Friday.