How to Calculate Business Days Between Two Dates

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Disclaimer: Results are computed from open-source holiday data and general conventions and may be incomplete or wrong (for example, regional, ad-hoc or newly declared holidays). They are not legal or financial advice. Verify any contractual, statutory or legally binding deadline against an official source before relying on it. API spec · Pricing & API keys

The method

Decide which end dates count. This calculator excludes the start date and includes the end date, the same convention used when adding business days. So from Monday to the following Monday is 5 business days, not 6.
Count the calendar days in the range.
Remove weekends. Each full week contributes 5 business days; handle the partial week at either end separately.
Remove public holidays that fall on weekdays inside the range, for the right country and region, plus any company closure days.

The holiday step is where spreadsheets usually go wrong: holidays that fall on a weekend are often observed on the Friday or Monday instead, and regional holidays differ within one country.

Worked example

From December 1, 2026 to December 31, 2026:

30 calendar days (December 2 through December 31).
Weekends only: 22 business days.
With US federal holidays: Christmas Day (Friday, December 25) is also excluded, so the answer is 21 business days.

The calculator above is prefilled with this example. Switch the country to see how other holiday calendars change the count.

In a spreadsheet

Excel and Google Sheets have NETWORKDAYS(start, end, holidays), but it includes both the start and end dates, so its result is often one higher than this calculator's, and you must maintain the holiday list yourself. If you need this inside software, the DueDate API endpoint /v1/business-days-between returns the count and the list of skipped days.

The same calculation is available as a JSON API, so you can run it inside an accounting, ERP or workflow system. Get a free API key (1,000 requests a month) or read the OpenAPI spec.

Holiday data comes from an open-source dataset and may be incomplete, especially for regional, ad-hoc or newly declared holidays. Check legally or financially critical deadlines against an official source.

Frequently asked questions

Are the start and end dates included?

This calculator excludes the start date and includes the end date. Spreadsheet NETWORKDAYS includes both, so its answer can be one higher.

How many business days are in December 2026 in the US?

From December 1 to December 31, 2026 there are 21 business days after excluding weekends and Christmas Day (22 if only weekends are excluded).

Can I exclude my own company holidays?

Yes. Enter them as comma-separated dates in YYYY-MM-DD format.

Which countries are supported?

The form offers the US, UK, Canada, Australia, Germany, France, Ireland, the Netherlands, Spain and Italy, with optional regions such as US states.