How to Calculate Business Days
What is Business Days?
A business days calculator counts working days between two dates, excluding weekends (Saturday and Sunday). Used for project timelines, delivery estimates, payment terms, and legal deadlines.
Formula
business_days = total_days - weekends - holidays
- start
- Start date (date) — Beginning date
- end
- End date (date) — Ending date
- business_days
- Business days (days) — Excludes weekends and holidays
Step-by-Step Guide
- 1Iterate through each calendar day between the two dates
- 2Skip days where getDay() returns 0 (Sunday) or 6 (Saturday)
- 3Count remaining days as business days
- 4For public holidays, subtract manually
Worked Examples
Input
Monday to Friday same week
Result
5 business days
Input
4 weeks calendar = 28 days
Result
20 business days
Input
30-day contract period
Result
~21–22 business days
Frequently Asked Questions
What counts as a business day?
Typically Monday–Friday, excluding public holidays. Different regions and companies define holidays differently.
Should I include the start and end dates?
Conventions vary. Usually: include start, exclude end (or vice versa). Check your company's definition.
How do I account for company holidays?
The calculator should allow you to input custom holidays. Bank holidays, Christmas, and company shutdowns are common exclusions.
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