This guide covers How to Calculate Business Days | TimeFlow — what it means, how it works, and how to use it. The explanations below are followed by worked examples with real dates and real times, a set of frequently asked questions, and links to the tools that do the calculation for you: the time zone converter, the world clock, and the UTC converter. Where a number is given — an offset, a date, a count — it is computed from the IANA Time Zone Database for the date stated, not copied from a table that may be out of date.

Try the tool: Time Zone Converter — convert any time between any two cities, with the daylight saving rules for the date you choose.

Business days are the weekdays in a range, minus the public holidays that fall on weekdays. The calculation has three steps: count the weekdays, list the holidays in the range, and subtract the ones that fall on weekdays.

Step one is the weekday count. Take the total days in the range, subtract the weekends. A quick way: each full week contributes 5 business days, and the remaining days contribute 1 each if they fall on a weekday. A month with 31 days that starts on a Monday has 23 weekdays; the same month starting on a Saturday has 21.

Step two is the holidays. Which holidays count depends on the country and, in the United States, on the state. Federal holidays are the usual list, but some employers also close on other days, and some industries work on holidays. The business days calculator on this site lets you add your own holidays, so the count matches your calendar.

Step three is the subtraction — and the edge cases. A holiday that falls on a Saturday is not a business day lost, because Saturday was not a business day anyway. A holiday that falls on a Sunday is observed on a Monday in some countries, and that Monday is the day to subtract. Getting these right is the difference between a correct count and a count that is off by one or two days.

In practice

The method is to count the weekdays in the range and subtract the public holidays that fall on weekdays. A range from Monday to Friday has five weekdays; if one of them is a public holiday, it has four business days. The business days calculator does it for any range, with the US federal holidays subtracted and your own holidays added.

The definition matters. A business day is a weekday that is not a public holiday — and the holidays depend on the country. The United States has eleven federal holidays; France has eleven public holidays; India has fifteen or more, depending on the state. A deadline of '10 business days' means something different in each country, and the difference is the holidays.

The practical use is deadlines. A contract that says 'delivery within 10 business days' means a fortnight from a Monday, not ten days — and the gap grows when a public holiday falls in the middle. Before you promise a date, count the business days: the business days calculator shows the count, the holidays, and the date that is a number of business days from now.

The numbers: the year 2026

2026 is not a leap year: it has 365 days, 52 full weeks and one extra day, and 53 ISO weeks (because it starts on a Thursday). There are 261 weekdays in the year and 104 weekend days. The next leap year is 2028, and the one after that is 2032; the century year 2100 will not be a leap year, because it is divisible by 100 but not by 400. 1 January 2026 was a Thursday, and 31 December 2026 will be a Thursday.

The extra day is the reason the calendar shifts: because 365 days is 52 weeks and one day, every date falls one weekday later the following year — two days later after a leap year. That is why your birthday is on a different weekday almost every year, and why the calendar repeats every 28 years in most cases. The week number finder gives the ISO week for any date, the date calculator works out what date it is a number of days from now, and the days between dates calculator counts the days between any two dates.

2027 is also not a leap year: it has 365 days, 52 ISO weeks, and 261 weekdays. It starts on a Friday and ends on a Friday. The next leap year after 2026 is 2028, which will have 366 days and 262 weekdays. The business days calculator counts the business days in any year, with the public holidays subtracted.

Key facts

  • A normal year has 365 days and a leap year has 366, with the extra day on 29 February.
  • A year has 52 full weeks and one extra day — or two in a leap year.
  • The Gregorian leap year rule: divisible by 4, except centuries, except centuries divisible by 400.
  • A business day is a weekday that is not a public holiday — and the holidays depend on the country.
  • In the ISO week system, the week starts on Monday and the first week is the one containing the first Thursday.

Frequently asked questions

How do I calculate business days?

Count the weekdays in the range and subtract the public holidays that fall on weekdays. The business days calculator does it for any range.

What is a business day?

A weekday that is not a public holiday. In the US that means Monday to Friday excluding the eleven federal holidays.

How many business days are in a month?

Usually 20 to 23, depending on the month and the holidays. February has the fewest; a 31-day month starting on a Monday has the most.

Do business days include Saturday?

Not usually. In most countries the working week is Monday to Friday — but in Israel Saturday is a working day, and in some industries Saturday is a business day.

How do I add business days to a date?

Count forward over weekdays, skipping weekends and holidays. The business days calculator gives the date that is a number of business days from now.

How many weekdays are there in 2026?

261 weekdays and 104 weekend days, out of 365 days in total. 2026 is not a leap year. The business days calculator counts the business days, with the public holidays subtracted.

What is the time difference between London and Tokyo?

Nine hours in January 2026: London is UTC+00:00 and Tokyo is UTC+09:00. In July it is eight hours, because London moves to UTC+01:00 while Tokyo stays on UTC+09:00. The time zone converter gives the difference for any two cities and any date.

Related pages

Sources

  • IANA Time Zone Database, via Node.js Intl (Intl.DateTimeFormat with timeZone) — offsets, daylight saving dates and local times in this article were worked out from the IANA database, not typed from memory.
  • TimeFlow's own time-zone data (data/cities.ts, data/dst.ts), computed from the IANA database.
  • Time zone rules and offsets: the IANA Time Zone Database, as applied by this site's tools. Offsets and daylight saving dates on this page are computed from the database for the dates stated.
  • TimeFlow's time zone converter, world clock and UTC converter — the live tools behind the numbers on this page.
  • Time-zone and daylight saving rules are set by governments and can change. For flights, deadlines and meetings that cannot move, confirm the time with an official source.