How to Count Business Days: When Is “3 Business Days Later”? First-Day Rules, Weekends and Holidays

Business days are “days you count while skipping days off”

A business day is a day on which a company or shop is actually operating. When counting, you skip the closed days and add up only the open days: 1, 2 and so on. That is the only difference from calendar days, but how many days you skip can change the result a lot.

• Calendar days: count every day on the calendar. “3 days later” is simply the date 3 days ahead.
• Business days: skip closed days. “3 business days later” moves further ahead on the calendar by however many weekends and holidays fall in between.
• What counts as a closed day depends on the company. Weekends plus public holidays is standard, but some shops close only on Sundays and some service desks are open every day.

In other words, “3 business days later” does not fix a date on its own. It becomes a concrete date only once two things are settled: (1) which day you start counting from, and (2) which days count as closed. Most disputes come from the sender and the receiver assuming different answers to these.

Start counting from the next business day (first day excluded)

In business, “N business days later” is usually counted with the business day after the base date as day 1. This is called excluding the first day. Article 140 of Japan's Civil Code also says that when a period is set in days, the first day is not counted, and this principle is the foundation for the practice.

1. 1

   Fix the base date

   This is the starting point, such as the order date, the payment date or the date documents were received. It is not counted.

2. 2

   Move to the next day

   Start looking from the day after the base date. If that day is a closed day, move on to the following day.

3. 3

   Count only business days

   Each time you land on an open day, count it as day 1, day 2 and so on. Closed days are not counted; you simply skip them.

4. 4

   The day you reach the target number is the answer

   For 3 business days later, the business day you count as day 3 is the date. Even if the base date is a closed day, you start counting from the next business day.

Checking with real dates

These examples treat weekends and Japanese public holidays as closed days. Using a Friday as the base date jumps far ahead on the calendar because of the weekend in between.

The third row crosses a week in which Japan's Respect for the Aged Day, a Citizens' Holiday and the Autumnal Equinox Day fall in a row. The same “3 business days later” ends up 10 days ahead on the calendar. Remember that a base date late in the week can push the date further than you expect.

“Within N business days” is a deadline; “N business days later” is a date

They look similar but play different roles. “Later” points to a single day, while “within” sets a deadline by which something must be finished. When it is written as a deadline, counting the same day as day 1 is not unusual.

When you write a notice yourself, the safest approach is to spell out the counting method too, for example “within N business days (counting today as day 1)”. When you are the one receiving it, work out the date both ways and act on the earlier one to keep the risk down.

Watch out when crossing long holidays

During Japan's Golden Week, the Obon summer break, the New Year period and the September holidays, a difference of a few business days becomes a difference of more than a week. Counting 3 business days from Tuesday, April 28, 2026 gives Thursday, May 7, which is 9 days ahead on the calendar.

• In years when a holiday falls on a Sunday, a substitute holiday adds one more day off.
• A weekday sandwiched between two public holidays becomes a Citizens' Holiday in Japan. September 22, 2026 is one of these.
• Company-specific days off, such as summer vacation or a founding anniversary, are not on the calendar. You need to check the other party's schedule in advance.
• Many Japanese companies close from December 29 to January 3, but the only statutory public holiday in that period is New Year's Day.

How Japan's public holidays are determined is summarized in a separate guide. When counting payment due dates, bank holidays need to be considered separately, so check the guide on payment due dates as well.

Counting with the tool

Counting by hand always mixes in missed holidays and misunderstandings about where to start. With the business day calculator, you just enter a base date and a number of days to get the date, and the days off that were skipped are listed with holiday names.

1. 1

   Match the closed-day settings to your company

   The default is weekends and holidays off. You can also choose “Weekends off (holidays open)”, “Sundays & holidays off” or “Open every day”, and add dates such as summer leave.

2. 2

   Enter a base date and a number of days in the “N business days after/before” tab

   1, 3, 5, 7, 10, 14, 20 and 30 business days are available as buttons. You can also count backward, “N business days before”, on the same screen.

3. 3

   Switch between including and excluding the first day

   You can compare both dates under the same conditions, so even if you don't know how the other party counts, you can see the range.

4. 4

   Check the days off that were skipped

   The closed days in between are listed with dates and reasons. Because holiday names are shown too, you can use the list to explain the date to the other party.

To count a period instead, use the “Business days in a period” tab; to see the number of days per month, use the “Annual calendar” tab. To count calendar days including weekends, such as “N days later” or the days between two dates, see how to calculate the days between dates.

FAQ

What exactly does “3 business days later” mean?

It is the day you reach after counting 3 days while skipping closed days such as weekends and holidays. The base date is normally not counted, so from a Friday you count Monday, Tuesday and Wednesday and land on the following Wednesday. For example, 3 business days after Friday, October 2, 2026 is Wednesday, October 7. A holiday in between pushes it later still, and across a long holiday it can be more than 10 calendar days ahead.

How do I count when the base date is a Saturday or a holiday?

Even if the base date is a closed day, you start counting from the next business day. For an order received on a Saturday, with the first day excluded, Monday is business day 1. The base date itself is not a business day, so it is not counted. If Monday is a holiday, it moves on to Tuesday. The tool lists the skipped days with reasons, so you can follow this step by step.

What is the deadline for “within 5 business days”?

It changes by one day depending on whether you count the same day as day 1 or start from the next day. Deadlines phrased as “within” are often counted including the same day, so for a request received on Monday, “within 5 business days” is usually read as the end of Friday. Some terms start from the next business day, so for important deadlines check the other party's terms or act on the earlier date.

Is there a law that defines how to count business days?

No Japanese law defines business days themselves. For counting days, Article 140 of the Civil Code says “the first day of a period is not counted”, so excluding the first day is the principle. However, agreements between the parties and industry practice take priority, so if a contract says “counted from the date of receipt”, that is the reference. Which days count as closed is also up to each company.

Can I calculate for a business that is closed on weekends but open on holidays?

Yes. In the tool's “Closed day settings”, uncheck the option that treats national holidays as closed days, or choose the “Weekends off (holidays open)” preset. You can also switch to Sundays-only closing or open every day. If you want to treat a specific holiday as a working day instead, add the date under the days you are specially open.