Published 1 January 2025 · 5 min read
How to Calculate Business Days (With and Without Holidays)
Whether you're tracking a contract deadline, calculating payroll periods, or estimating delivery dates, knowing how to count business days accurately is essential. A business day is any day that falls on a standard working day — typically Monday through Friday — and is not a public holiday.
The manual method
To count business days between two dates by hand, start from the day after your start date and count each weekday until you reach the end date. For each week, that's five working days. Then subtract any public holidays that fall within that range.
For example, if you need to count business days from Monday 6 January to Friday 17 January 2025, that's two full working weeks — 10 business days. If a bank holiday falls on one of those days, subtract one to get 9.
When business day counts matter
Business day calculations are critical in several real-world scenarios:
- Contracts and legal deadlines — many contracts specify notice periods or response times in "business days" rather than calendar days.
- Service level agreements (SLAs) — support teams often measure response times in business days to exclude weekends and holidays.
- Payroll processing — pay periods and cut-off dates are almost always defined in business days.
- Shipping and delivery — estimated delivery windows typically exclude weekends and public holidays.
- Project planning — accurate business day counts help set realistic milestones and deadlines.
Why it gets complicated
The tricky part is handling public holidays. Different countries — and even different regions within the same country — observe different holidays. The UK alone has separate bank holiday schedules for England & Wales, Scotland, and Northern Ireland.
On top of that, some countries use Friday and Saturday as their weekend rather than Saturday and Sunday, which changes the base calculation entirely.
The easy way: use a calculator
Skip the manual counting
Our Business Days Calculator handles weekends, public holidays, and different weekend patterns for 50+ countries — instantly.
Open Business Days CalculatorTips for accurate counts
When counting business days, keep these tips in mind:
- Always clarify whether the start and end dates are included in the count.
- Check which country's holiday calendar applies — especially for international contracts.
- Remember that bank holidays can change from year to year (e.g. the UK's early May bank holiday was moved in 2020 and 2022).
- For recurring calculations, consider whether your weekend pattern is Saturday-Sunday, Friday-Saturday, or Sunday-only.
Getting business day counts right can save time, prevent disputes, and keep projects on track. Whether you count manually or use a tool, accuracy matters.
