How to Count Business Days Between Two Dates

To count business days between two dates, include both the start and end dates, drop every Saturday and Sunday, then subtract any public holidays that fall on a weekday — or paste the two dates into a business days calculator and read the working-day total instantly. This guide shows the manual logic and the faster in-browser method.

What counts as a business day

A business day is a working day: Monday through Friday, excluding weekends and any holidays your organisation observes. That distinction matters because SLAs, delivery windows and leave balances are almost always quoted in working days, not raw calendar days. A ten calendar-day gap can be anywhere from six to eight business days once you strip out weekends and holidays.

Count business days in four steps

1. Pick the start and end dates. Choose the first and last day of your period. Both ends are included in the count.
2. Add your holidays. Optionally paste public holidays into the holiday box, one date per line in YYYY-MM-DD format, for example 2026-12-25.
3. Let the tool exclude non-working days. Saturdays, Sundays and any listed holiday that lands on a weekday are removed automatically.
4. Read the breakdown. You get the business-day count alongside weekend days and the total calendar span, so the whole period is easy to verify.

A worked example

Suppose a project runs from Monday 1 June 2026 to Friday 12 June 2026, and 5 June is a company holiday. Here is how the days break down:

Category	Count
Total calendar days	12
Weekend days (6, 7 June)	2
Holidays on a weekday (5 June)	1
Business days	9

Twelve calendar days minus two weekend days minus one weekday holiday leaves nine working days — the figure you would put on a delivery estimate or a leave form.

Why the inclusive count matters

The calculator counts both the start and end date, which matches how most SLAs and delivery windows are quoted. A period that runs Monday to Friday of the same week is five business days, not four. If you only need the gap between two dates, remember that this inclusive convention adds one day compared with a pure difference. The tool also handles reversed ranges gracefully, so swapping start and end still returns a sensible count.

Private for HR and client data

All the counting runs locally in your browser with JavaScript. Your dates and holiday lists are never uploaded, logged or stored, which makes the calculator safe for internal HR figures, leave records and confidential client-project timelines. Once the page has loaded it also works offline.

Try the Business Days Calculator — free and 100% in your browser.

FAQ

What date format should I use for holidays?

Enter each holiday on its own line using YYYY-MM-DD, for example 2026-01-01. Any listed date that falls on a working day is subtracted from the business-day total; holidays that already land on a weekend make no difference.

Does the calculator count the first day?

Yes. The range is inclusive of both the start and end dates, so a single working day selected as both start and end counts as one business day. This mirrors how delivery and SLA windows are normally quoted.

Can I use it for a four-day working week?

The tool treats Saturday and Sunday as the weekend by default. If your week is shorter, add your regular non-working weekday as a recurring entry in the holiday list for each date in the range to exclude it from the total.

What if my end date is before my start date?

The calculator handles reversed ranges gracefully and still returns the number of working days in the span, so you do not have to worry about the order you enter the two dates.

Related free tools

• Date Difference Calculator — get the raw gap in days, weeks and months.
• Add or Subtract Days Calculator — project a date forward or backward.
• Days Until Date Calculator — count down to an upcoming deadline.
• Weekday Finder — check which day of the week any date falls on.

Built by ByteVancer

ByteTools is a free product of ByteVancer, a software and web development studio building web apps, SaaS and custom software. If your team needs scheduling logic baked into a real product, explore what ByteVancer can build for you.