Business Days Calculator
Count working days between two dates, or find the date a given number of working days away — with custom working days and your own holiday list.
How to use this calculator
- 1Choose whether you are counting days between dates or projecting forward.
- 2Adjust the weekend pattern if your working week is not Monday to Friday.
- 3Paste your public holidays, one per line in YYYY-MM-DD format, to exclude them.
How the calculation works
Working days = Calendar days − Weekend days − Holidays falling on weekdays- Weekend days
- Days matching your selected weekend pattern
- Holidays
- Dates you supply, counted only if they fall on a working day
A holiday that falls on a weekend is not deducted twice — it was already excluded.
For projecting a deadline, day one is the next working day after the start, which matches how business-day service levels are normally written.
Worked example
Working days from 10 August to 25 December 2026
- 1.The span covers 138 calendar days including both endpoints.
- 2.Of those, 40 fall on a Saturday or Sunday.
- 3.138 − 40 = 98 working days, before any public holidays are excluded.
Result: 98 working days
Why business days are counted differently from calendar days
Not every day carries equal weight for scheduling. A courier quoting "three business days" is making an implicit promise about when staff are actually working to move a shipment — weekends and public holidays do not count, because nothing happens on them from the business’s side. Treating every day the same when a process only actually runs five days a week produces deadlines that are quietly, systematically wrong: early in an estimate, late in reality.
The gap between the two counts grows with however many non-working days fall inside the span. A single public holiday only shifts a delivery date by a day, but a span crossing a major holiday period, or one falling in a place with an unusually high number of public holidays, can shift by a week or more.
The five-day week is younger than it looks
A Monday-to-Friday working week feels like a fact of nature, but it is a comparatively recent standard. Through the nineteenth and early twentieth centuries, a six-day working week was the norm across most industrial economies, with only Sunday reliably off. Ford Motor Company was among the first major employers to break from that pattern, moving its factory workers to a five-day, forty-hour week on 1 May 1926 without cutting their pay — a decision Henry Ford defended on the then-unusual grounds that workers with a full weekend of leisure time would also have more time to spend as consumers. The pattern spread gradually across American industry over the following decades and became the assumed default that scheduling tools like this one still use.
Not every country weekends on the same days
The five-day week generalized, but which two days make up the "weekend" never fully standardized worldwide. Saturday and Sunday are the norm across most of the Americas, Europe and East Asia, but several countries with a Friday congregational prayer tradition have instead treated Friday and Saturday as the non-working days — Saudi Arabia among them, though a number of Gulf states have shifted toward a Saturday–Sunday or hybrid weekend over the past decade specifically to align their business week more closely with international markets. A calculator that silently assumes Saturday and Sunday will misdate every deadline for a business operating on a different weekend, which is why the weekend pattern here is a choice rather than a fixed assumption.
Where business-day counting actually gets used
The habit of measuring time in working days rather than calendar days shows up across almost every industry that makes promises about when something will happen.
- Shipping and delivery SLAs — "ships in 2 business days" is a promise about working time, not calendar time, and the two diverge fast around holidays.
- Legal and contractual notice periods — many jurisdictions define notice periods — eviction, termination, appeal windows — in business days specifically, not calendar days.
- Financial settlement — securities trades commonly settle a fixed number of business days after the trade date, often written as T+1 or T+2.
- Government and administrative processing — visa, passport and permit processing times are usually quoted in business days, because the offices doing the work are themselves closed on weekends and public holidays.
- Payroll and invoicing — pay dates and payment terms, such as "net 30 business days", are anchored to the working calendar rather than the plain calendar.
What this assumes, and where it stops
Assumptions
- Working days are every day that is not in your selected weekend pattern and not in your holiday list.
- Holidays must be supplied — none are assumed, because they vary by country, region and year.
Limitations
- No built-in holiday calendars. Regional variation is large enough that a wrong default would be worse than none.
- Does not model half-days, company shutdowns, or partial working days.
Common questions
Does the start date count as day one?
When counting between dates, you choose — the "count the start date" switch controls it. When projecting forward, day one is the next working day after the start, which is the standard convention for business-day deadlines and service level agreements.
Why are public holidays not filled in automatically?
Because they differ by country, by region within a country, and by year — and some move with the lunar calendar. A wrong default would silently produce wrong deadlines, which is worse than asking you to paste in the dates that actually apply to you.
Formula and content last reviewed on .
Results are estimates for information only, not professional advice.
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