How business days are counted

By Niraj Kumar · Published October 28, 2026

Deadlines, delivery estimates, notice periods and payment terms are written in business days, and a count that is off by one is the most common cause of a missed one. The business days calculator adds or counts working days with a country’s holidays applied; this guide is about the conventions that decide what the right answer is, because there is more than one and they differ by a day or two.

What a business day is

A business day is a day that is neither a weekend day nor a public holiday in the relevant place. The weekend is Saturday and Sunday in most of the world, and the holidays are those of the country, and sometimes the state or province, whose calendar governs the deadline. That last point is the one most often forgotten: a contract between a company in Sydney and one in Munich has to say which country’s holidays apply, or Australia Day and Whit Monday will each be a business day to one side and not the other.

Counting forward: does today count?

“Three business days from Monday” is Thursday under the usual rule, which counts the days after the start date and does not count the start date itself. Monday is day zero; Tuesday, Wednesday and Thursday are days one to three. The alternative, counting Monday as day one, gives Wednesday, and some legal rules work that way. Rules also differ when the start date is itself a weekend or a holiday: some move to the next business day and count from there, which makes three business days from a Saturday Thursday, while a plain count of the days after the start makes it Wednesday. The workdays calculator uses the plain count: it never counts the start date, and it lists every day it skipped so you can see which rule you are applying.

The same ambiguity exists for intervals. The number of business days between Monday and Friday of the same week is four if the count is exclusive of one end and five if both ends are included. A delivery window “within five business days” almost always means the exclusive count; a count of days worked in a period includes both ends. The business days calculator reports the inclusive count for a date range and labels it as such.

Holidays that fall on weekends

When a public holiday lands on a Saturday or Sunday, many countries move the day off to a weekday, and the rule differs. The United States observes a Saturday holiday on the preceding Friday and a Sunday holiday on the following Monday. The United Kingdom, Australia, New Zealand and Canada substitute the next weekday, so a Saturday holiday becomes Monday and a Sunday holiday also becomes Monday, or Tuesday if Monday is already taken, as happens when Christmas Day falls on a Saturday and Boxing Day on a Sunday. Many countries in Europe, Asia and Latin America do not substitute at all, and the holiday is simply lost that year. A business-day count has to apply the observed date, not the nominal one, and this site’s holiday data records the observed days for the countries it covers.

Where the weekend is not Saturday and Sunday

Several countries in the Middle East and North Africa keep a Friday and Saturday weekend: Saudi Arabia, Qatar, Kuwait, Bahrain, Oman, Egypt, Jordan and others. Israel’s weekend is Friday and Saturday too, with Sunday a working day. The United Arab Emirates moved in 2022 to a Saturday–Sunday weekend with a half day on Friday, and Nepal takes only Saturday off. A business-day count across any of these borders changes by a day a week. The calculator lets the weekend be set per calculation; the holidays page lists what it knows for each country.

Half days, bank holidays and sector holidays

“Business day” and “bank holiday” are not quite the same list. Christmas Eve and New Year’s Eve are half days or full days off in many offices without being public holidays; stock exchanges keep their own calendars, which differ from the civil one; courts have their own non-sitting days; and some countries have regional holidays that apply in one state and not the next. A count that matters, such as a legal notice period or a settlement date, should use the specific calendar the rule names, and a general-purpose calculator is a check rather than the authority.

The spreadsheet functions

Excel and Google Sheets provide NETWORKDAYS(start, end, holidays) for an inclusive count of working days between two dates, and WORKDAY(start, days, holidays) to add a number of working days to a date, which does not count the start date. The .INTL variants take a weekend code or a seven-character mask so that a Friday–Saturday weekend, or a single day, can be specified. The holidays argument is a range of dates you supply; nothing in the function knows any country’s calendar, so the list has to be right and has to include observed dates. The conventions match the ones described above, which is why a count from this site and from a spreadsheet with the same holiday list should agree.

Writing a deadline that cannot be misread

State the number of business days, the calendar that applies, whether the start date counts, and the resulting date in full. “Within five business days (UK calendar, excluding the date of receipt), that is by Friday 6 November 2026” leaves nothing to interpret. For anything crossing a border, name the country whose holidays apply. And when a deadline matters, compute it twice, once by hand on a calendar and once with a tool, because the ways to be a day out are exactly the ones a quick count hides.