Business Days Calculator

How to use it

1. Pick your dates. The end date is included by default, because “Monday to Friday” means five days to most people.
2. Set your weekend. Saturday-Sunday is the default, but it is not the only option and for a lot of the world it is the wrong one.
3. Choose public holidays for your country, or add your own.
4. Check the list. Every holiday the tool deducted is named, so you can verify the number instead of trusting it.

Weekends are not Saturday and Sunday everywhere

This is the assumption most working-day calculators bake in, and it quietly gives the wrong answer to a large part of the world.

The gap is worth putting numbers on. Take 1 to 31 August 2026:

Five days is a fortnight’s difference over a quarter. On a contractual deadline or a payroll calculation, that is not a rounding error.

Public holidays

Holidays are computed from rules rather than looked up in a table, so they are correct for any year you ask about rather than only the years someone remembered to update.

Three kinds of rule cover almost everything:

• Fixed dates — Christmas Day, 4 July, India’s Republic Day on 26 January.
• Nth weekday of a month — US Thanksgiving is the fourth Thursday in November; the UK’s Spring Bank Holiday is the last Monday in May.
• Easter-based — Good Friday is two days before Easter Sunday, Easter Monday the day after, and Germany’s Ascension and Whit Monday are 39 and 50 days after. Easter itself is computed with the standard Gregorian algorithm, verified against known dates from 1990 to 2050.

Why some holidays are missing, and what to do about it

Some of the world’s most widely observed holidays cannot be computed from a Gregorian rule at all.

Eid al-Fitr and Eid al-Adha follow the lunar Hijri calendar, and in many countries the exact date is confirmed only by moon sighting a day or two beforehand. No algorithm can tell you in advance what a religious authority will announce.

Diwali, Holi, Chinese New Year, Vesak Day and many others follow lunisolar calendars whose rules are complex and, for some, regionally variable.

So for India, Pakistan and Singapore the tool includes only the fixed-date and Easter-based holidays, and it says so on screen when you pick one of those countries. That is a real limitation and we would rather name it than quietly return a number that is too high.

The fix is the custom holidays box. Paste in the dates for your year and they are deducted like any other. Your HR department or national gazette will have them.

Two more caveats worth knowing regardless of country. Regional and state holidays vary within countries — a calculation for Bavaria is not a calculation for Berlin. And when a fixed-date holiday falls at a weekend, most countries grant a substitute day on the following Monday, but the rules for that differ by jurisdiction and are not applied here.

The date after N working days

The second mode answers the other half of the question. Contracts and service-level agreements are almost never written in calendar days — they say “within 10 working days” or “30 business days from receipt”.

Enter a start date and a number, and the tool counts forward, skipping weekends and holidays as it goes. Negative numbers count backwards, which is how you work out when something had to be filed to meet a deadline.

Those assume a Saturday-Sunday weekend and no public holidays. Notice how neatly five working days maps onto a calendar week — that is the useful mental shortcut, and it breaks the moment a holiday appears.

Worked example

An invoice issued on Monday 3 August 2026 with 20 working days to pay, under UK bank holidays.

• The Summer Bank Holiday falls on Monday 31 August 2026, the last Monday in August.
• Without it, 20 working days lands on Monday 31 August.
• With it deducted, the due date moves to Tuesday 1 September 2026.

One holiday, one day of difference — and if you had assumed calendar days instead, you would have said 23 August and been over a week early.

What the working days calculator counts

Any day that is not a weekend and not a public holiday. That is the definition this tool uses and the one most contracts assume.

A few things it deliberately does not model, because they vary by employer rather than by country: half-days, company shutdowns between Christmas and New Year, shift patterns, and annual leave. If those matter, add them as custom holidays.

The totals always reconcile — working days plus weekend days plus holidays equals calendar days. If a holiday falls on a weekend it is counted once, as a weekend day, rather than being deducted twice. That sounds obvious, and getting it wrong is a common bug that makes the numbers fail to add up.

Doing it elsewhere

In every case you supply the holiday list yourself — no spreadsheet ships with one.

Related

For plain calendar days including both endpoints, use the date duration calculator. The age calculator shares the same date engine. If your deadline involves people in other countries, the time zone converter will tell you whether a daylight saving change falls in the way.