What counts as a business day?

A business day is any day that is considered a working day in your calendar. By default this means Monday to Friday, excluding weekends and any holidays you choose to add. You can change the weekend pattern if your workweek is different.

Are the start and end dates included in the business day count?

You can choose. The calculator has an option to include or exclude the start date. The end date is always included if it is a working day. The summary under the result clearly shows what was included.

How are holidays handled?

Any date you add to the Holidays list is treated as a non-working day, even if it falls on a weekday. Holidays that fall on weekends are ignored because they are already non-working days unless you changed the weekend pattern.

Can I use this calculator for countries with different weekends?

Yes. You can choose between common weekend patterns such as Saturday–Sunday, Friday–Saturday, or Sunday–Monday, or define a fully custom workweek by toggling which weekdays are working days.

What is the difference between calendar days and business days?

Calendar days count every day between two dates, including weekends and holidays. Business days only count days that are marked as working days in your settings, excluding weekends and any holidays you have added.

Business Days Calculator

Count working days between two dates or add/subtract business days from a date. Customize weekends, holidays, and workweek patterns.

Start date

End date

Include start date if it is a working day

Workweek & weekend settings

Weekend pattern

Choose which days are treated as weekends (non-working days).

Holidays & non-working dates

Optional

Holiday date

Label (optional)

No holidays added.

Holidays are treated as non-working days even if they fall on a weekday.

How this business days calculator works

This tool lets you quickly calculate working days for scheduling, payroll, project planning, SLAs, and deadlines. It supports two modes:

Between two dates – count how many business days fall between a start and end date.
Add / subtract business days – move forward or backward by a given number of working days from a starting date.

You can customize which days are weekends, define a custom workweek, and add any number of holidays that should be treated as non-working days.

Definition of a business day

In this calculator, a business day (or working day) is any date that:

Is marked as a working weekday in your settings, and
Is not a weekend day, and
Is not in your list of holidays.

Counting business days between two dates

Suppose you choose a start date \(S\) and an end date \(E\) (with \(S \le E\)). The calculator:

Builds the full list of calendar dates from \(S\) to \(E\) (inclusive).
Optionally removes \(S\) if “include start date” is unchecked.
For each remaining date:
- Checks if it is a working weekday (based on your weekend pattern or custom workweek).
- Checks if it is not in the holiday list.
Counts all dates that pass both checks as business days.

Business days formula (conceptual)

Let \(D\) be the set of all dates between \(S\) and \(E\) (inclusive, or exclusive of \(S\) if you choose). Then:

\[ \text{Business days} = \left| \{ d \in D \mid d \text{ is a working weekday and } d \notin H \} \right| \]

where \(H\) is the set of holidays you entered.

Adding or subtracting business days

When you add or subtract business days, the calculator walks day by day from the start date, skipping weekends and holidays until the requested number of working days has been counted.

If you include the start date, it is counted as the first business day if it is a working day.
If you exclude the start date, counting begins on the next calendar day.

Typical use cases

Finding a project deadline that is 30 business days from today.
Calculating lead times or service-level agreements (SLAs) in working days.
Determining how many billable days fall in a contract period.
Checking if a payment due date lands on a weekend or holiday.

Tips for accurate results

Always add your country’s public holidays that fall within the date range.
If your company has additional company-wide shutdown days, add them as holidays too.
Use the custom workweek option if you work night shifts, rotating schedules, or non-standard weeks.
Check the calendar view to visually confirm which days were counted or skipped.