Business Days, Operating Days and Weekdays: What’s the Difference? | Using Them in Contracts and Notices
“Within 3 business days”, “20 operating days”, “weekdays only”. They all seem to mean days other than weekends, but public holidays may be treated differently, and the definition can even change from company to company. This guide sorts out calendar days, weekdays, business days, operating days and working days, using Japan as the example, and shows how to write notices and contracts so they are not misread.
What the five terms mean
The words used for counting days look alike but point to different things. Start with the overall picture in the table.
| Term | What it means | Public holidays? |
|---|---|---|
| Calendar day | Every day on the calendar | Included (no distinction) |
| Weekday | Any day other than Saturday and Sunday | Often included |
| Business day | A day the company does business | Depends on the company (usually off) |
| Operating day | A day the factory or site is running | Depends on the company |
| Working day | A day employees are required to work | Depends on the work rules |
None of these has a definition set by law. Only calendar days are fixed objectively; the other four do not settle on a date unless you add “for whom”. When you use them in a notice, you need to write with that ambiguity in mind.
Do weekdays include public holidays?
This is where disputes happen most. In the dictionary sense a weekday is a day that is not a holiday, but in everyday use it often means “a day that is not Saturday or Sunday”, so some people count public holidays as weekdays.
- A shop that says “open weekdays only” is closed on a public holiday, and customers are caught out.
- Writing a mix such as “10 weekday business days” leaves it unclear how public holidays are treated.
- You only meant the days of the week but wrote “weekdays”, and people ask whether public holidays are included.
Business days and operating days differ by company
A business day is “a day the company is open for business”, so there are as many definitions as there are companies. The same “5 business days” lands on a different date if the other party has different closing days.
| Closing-day pattern | Business days in 2026 (Japan) | Examples |
|---|---|---|
| Closed on weekends and public holidays | 244 days | Most companies and government offices |
| Closed on weekends (open on public holidays) | 261 days | Some service and logistics businesses |
| Closed on Sundays and public holidays | 296 days | Small shops and some factories |
| Open every day | 365 days | Convenience stores and some e-commerce support |
“Operating day” is common in manufacturing and means a day the factory line is running. There are days when the office is open but the factory has stopped (for stocktaking or equipment inspection), so business days and operating days may not match even within one company. When discussing production plans or delivery dates, it is safer to confirm which meaning is intended.
“Working day” is seen from the employee’s side and corresponds to the scheduled working days set in the work rules. How many there are in a year can be worked out backwards from the annual number of holidays, as covered in annual business days and scheduled working days.
Business days for banks, government offices and delivery services
Apart from your own company calendar, you also need to know the business days of the institutions involved in a transaction. In Japan these are set by law or regulation, so they do not vary from company to company.
- Banks: under the Banking Act, Saturdays, Sundays, public holidays and 31 December to 3 January are bank holidays. Besides counters being closed, this affects when transfers arrive.
- Government offices: under the act on holidays of administrative bodies, Saturdays, Sundays, public holidays and 29 December to 3 January are holidays. The year-end break is one or two days longer than for banks.
- Securities market: the Tokyo Stock Exchange is closed on weekends, public holidays and 31 December to 3 January. Settlement is counted as 2 business days after the trade date (T+2).
- Delivery companies: many operate almost every day, but pickup and delivery stop for a period around the New Year.
How to write it in contracts and notices
Precisely because these words are loosely defined, adding a short clarification in documents prevents differences in interpretation.
- Say whose business days you mean, as in “5 business days (excluding our closing days)”.
- Put a closing-day calendar somewhere on your website and point to it from your notices.
- State when counting starts. Writing “counted from the day after receipt” settles that the first day is not counted.
- Decide what happens if a deadline falls on a holiday. “Moved to the next business day” is the usual rule.
- For anything counted in calendar days, write “within 30 days (including weekends and public holidays)” to distinguish it from business days.
If you are unsure how to count, see how to count business days. You can check the actual number of days on the “business days in a period” tab of the Business Day Calculator, which also lists each closed day with its reason.
FAQ
- What is a business day? Are weekends and public holidays always excluded?
- A business day is a day a company or shop is doing business, and there is no legal definition. Because many companies close on weekends and public holidays, it is often used to mean “days other than weekends and public holidays”, but for a shop closed only on Sundays or a service open every day, the meaning changes. When dealing with another company, checking its closing-day calendar is the reliable way.
- How do business days and operating days differ?
- Business days are days the company is open; operating days are days the factory or site is running. In manufacturing, the line may stop for equipment inspection or stocktaking while the office is open, and such a day is a business day but not an operating day. Delivery dates are sometimes based on operating days, so confirming which is meant prevents misunderstandings.
- Do weekdays include public holidays?
- It depends on who is using the word. In the dictionary sense a weekday is a day that is not a holiday, so public holidays are not included, but in practice it often means “days other than Saturday and Sunday” and public holidays get counted. In notices, write “weekdays (excluding public holidays)” or “Monday to Friday”. When counting days, using business days instead of weekdays reduces confusion.
- Should I count in calendar days or business days?
- It depends on what is being counted. Periods set by law, such as notice of contract termination or the cooling-off period for consumer contracts, are in principle counted in calendar days. Things that cannot progress unless the other party is working, such as shipping or bank transfers, are counted in business days. If a document just says “days”, it is normally read as calendar days, so always say so when you mean business days.
- How are bank business days decided in Japan?
- The Banking Act and its enforcement order set Saturdays, Sundays, national holidays and 31 December to 3 January as bank holidays. Government offices are closed from 29 December to 3 January, so their year-end break is a little longer. The Business Day Calculator has a setting to treat the New Year period (29 December to 3 January) as closed, and by adjusting additional closing days you can count in a way close to the bank calendar.
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