What does “3 business days later” mean?

It is the date you reach after counting 3 days while skipping weekends, holidays, and other days off. The usual way is not to count the base date, so if the base date is a Friday, 3 business days later is the following Wednesday (counting Monday, Tuesday, Wednesday and skipping the weekend). If a holiday falls in between, the date moves back even further, so this tool shows the days off it skipped over with their dates and holiday names.

Do “within 3 business days” and “3 business days later” mean the same thing?

Sometimes they differ. “Within” expresses a deadline, and it is not unusual to count the day itself as day 1. Which way to count depends on the other party’s terms or the trading conditions, so this tool lets you switch between “include the first day” and “exclude the first day” and check both dates.

Are business days, working days, and weekdays the same thing?

“Weekdays” means days other than weekends, and in some usages it includes public holidays. A business day is a day a company is open, and a working day is a day a factory or site is operating; both are decided by each company. In this tool you can set the closed weekdays, holidays, and your own days off, so you can count according to your company’s definition.

Can it calculate when weekends are off but holidays are working days?

Yes. In “Closed day settings”, uncheck “Treat national holidays as closed days”, or choose the preset “Weekends off (holidays open)”. You can also switch to a Sunday-only closure for shops, or to open every day.

Can I add my company’s own days off, such as summer leave or a founding anniversary?

Write one date per line in “Additional closed days” and those days are counted as closed. Formats such as “2026-08-13” and “8/14” are supported, and if you omit the year it is read as the year being calculated. Conversely, if you work on a holiday, write that date under “Special working days” and it is counted as a business day.

How is a substitute holiday decided?

When a national holiday falls on a Sunday, the nearest following day that is not a holiday becomes a day off (Article 3, paragraph 2 of the Act on National Holidays). For example, when May 3 is a Sunday, May 4 and 5 are also holidays, so May 6 becomes the substitute holiday. This tool determines and shows it automatically.

Why do some years have a “citizens’ holiday” in September?

Because there is a rule that a weekday sandwiched between two holidays becomes a day off (Article 3, paragraph 3 of the Act on National Holidays). It occurs in years when exactly one day separates Respect for the Aged Day (third Monday of September) and the autumnal equinox day, producing what is called Silver Week. This tool counts it as a closed day under “citizens’ holiday”.

Are holidays more than a year ahead displayed correctly?

Holidays with fixed dates and Happy Monday holidays can be calculated correctly any number of years ahead. However, the spring and autumn equinox days are officially decided in the official gazette each February for the following year, so later years use estimated dates from astronomical calculation. Years that include an estimate are marked on the screen.

Can I get business days per month or scheduled working days per year?

Choose a year in the “Annual calendar” tab and the calendar days, business days, and closed days for January to December are listed in a table, along with yearly totals. The table can be copied as tab-separated text and pasted straight into a spreadsheet.

Does the number of days in a period include the start and end dates?

By default both ends are counted (“September 1 to September 30” is 30 days). If you want to exclude the first day, as in “counting from ◯”, or count only up to the day before the closing date, switch the setting under “How to count days”.

Can bank business days be counted in the same way?

Banks are closed on weekends and holidays plus December 31 to January 3, so you get close by using the “Weekends and holidays off” setting, turning on “Treat the New Year break (12/29–1/3) as closed”, and removing December 29–30 from the additional closed days. However, when a transfer arrives differs by financial institution and service, so follow the recipient’s notice for the final check.

Can I share the conditions I calculated with someone else?

Press “Copy link to these conditions” at the bottom of the screen and a URL containing the dates and numbers is copied. Whoever opens the link sees the same conditions already filled in. The results themselves can be copied as text with the copy button.

Business Day Calculator (Days Excluding Weekends & Holidays, N Business Days Later)

Enter a start and end date and it counts the business days, excluding weekends, public holidays, and the New Year break. It also handles delivery and payment due date questions like “what date is 3 business days from today?”, and lists the days off in between with holiday names. Japanese national holidays, including substitute holidays, citizens’ holidays, and the spring and autumn equinox days, are determined automatically. You can set which weekdays are closed and add your company’s own days off, and the annual calendar tab shows business days per month (a guide to scheduled working days).

ABOUT

About Business Day Calculator (Days Excluding Weekends & Holidays, N Business Days Later)

The business day calculator counts days while excluding weekends, public holidays, the New Year break, and other days off. It has three tabs: “Period”, which gives the number of business days between a start and end date; “N business days after/before”, which counts from a base date; and “Annual calendar”, which shows business days per month. Japanese national holidays are determined automatically, including Happy Monday holidays, substitute holidays, citizens’ holidays sandwiched between two holidays, and the spring and autumn equinox days whose dates change every year. You can change which weekdays are closed and add company-specific days off such as summer leave or a founding anniversary.

How to use Business Day Calculator (Days Excluding Weekends & Holidays, N Business Days Later)

1In “Closed day settings”, choose which weekdays are days off (the default is weekends and public holidays off)
2If your company has its own days off, such as summer leave or the New Year break, add the dates one per line
3In the “Business days in a period” tab, enter a start and end date to see the number of business days and a breakdown of closed days
4In the “N business days after/before” tab, enter a base date and a number of days to get the date for a delivery or payment deadline
5In the “Annual calendar” tab, choose a year to see business days per month and the list of holidays

Great for

Check the actual date for deadlines such as “ships within 3 business days” or “payment arrives in 5 business days”
Count the payment due date of an invoice in business days, skipping weekends and holidays
Check how many holidays fall in between before deciding the delivery date on a quotation or contract
Count the working days in a period for leave requests or project schedules
Work out monthly and yearly business days to plan scheduled working days or work shifts
Look up next year’s holidays all at once, including substitute holidays

Good to know

Holidays are calculated according to the Act on National Holidays. Substitute holidays (the next weekday when a holiday falls on a Sunday) and citizens’ holidays (a weekday sandwiched between two holidays) are also counted as days off.
The spring and autumn equinox days are fixed each February by the National Astronomical Observatory of Japan (published in the official gazette). For later years, estimated dates from astronomical calculation are shown, and the screen says so.
By default, “N business days after” is calculated without counting the base date (“exclude the first day”). If your practice counts the day itself as day 1, switch to “include the first day”.
In the breakdown of closed days, only one reason is counted per day. A holiday that falls on a Sunday is counted under “closed weekdays”, so the breakdown always adds up to the total number of closed days.
Dates you enter under “Special working days” are counted as business days even if they are weekends or holidays.
Bank counters are closed on weekends, holidays, and from December 31 to January 3, but that is not necessarily the same as your company’s business days. For when a transfer arrives, also check the financial institution’s calendar.
The dates and settings you enter are processed only in your browser and are never sent to a server.

Questions this tool answers

Use Business Day Calculator (Days Excluding Weekends & Holidays, N Business Days Later) for searches like these:

I want to know what date is 3 business days from today
I want the date 5 or 10 business days later, skipping weekends and holidays
I want to check exactly which day “within 3 business days” is
I want to count the business days in a period excluding weekends and holidays
I want to know how many business or working days there are this month
I want to count an invoice payment due date in business days
I want to check how many holidays fall before the delivery date
I want an estimate of scheduled working days per year
I want a list of next year’s holidays
I want to know when the substitute holiday falls
I want to check when the September holiday streak (Silver Week) is
I want to count business days with my own company calendar including summer leave
I want business days when weekends are off but holidays are working days
I want to know the difference between business days, weekdays, and working days

FAQ

What does “3 business days later” mean?: It is the date you reach after counting 3 days while skipping weekends, holidays, and other days off. The usual way is not to count the base date, so if the base date is a Friday, 3 business days later is the following Wednesday (counting Monday, Tuesday, Wednesday and skipping the weekend). If a holiday falls in between, the date moves back even further, so this tool shows the days off it skipped over with their dates and holiday names.
Do “within 3 business days” and “3 business days later” mean the same thing?: Sometimes they differ. “Within” expresses a deadline, and it is not unusual to count the day itself as day 1. Which way to count depends on the other party’s terms or the trading conditions, so this tool lets you switch between “include the first day” and “exclude the first day” and check both dates.
Are business days, working days, and weekdays the same thing?: “Weekdays” means days other than weekends, and in some usages it includes public holidays. A business day is a day a company is open, and a working day is a day a factory or site is operating; both are decided by each company. In this tool you can set the closed weekdays, holidays, and your own days off, so you can count according to your company’s definition.
Can it calculate when weekends are off but holidays are working days?: Yes. In “Closed day settings”, uncheck “Treat national holidays as closed days”, or choose the preset “Weekends off (holidays open)”. You can also switch to a Sunday-only closure for shops, or to open every day.
Can I add my company’s own days off, such as summer leave or a founding anniversary?: Write one date per line in “Additional closed days” and those days are counted as closed. Formats such as “2026-08-13” and “8/14” are supported, and if you omit the year it is read as the year being calculated. Conversely, if you work on a holiday, write that date under “Special working days” and it is counted as a business day.
How is a substitute holiday decided?: When a national holiday falls on a Sunday, the nearest following day that is not a holiday becomes a day off (Article 3, paragraph 2 of the Act on National Holidays). For example, when May 3 is a Sunday, May 4 and 5 are also holidays, so May 6 becomes the substitute holiday. This tool determines and shows it automatically.
Why do some years have a “citizens’ holiday” in September?: Because there is a rule that a weekday sandwiched between two holidays becomes a day off (Article 3, paragraph 3 of the Act on National Holidays). It occurs in years when exactly one day separates Respect for the Aged Day (third Monday of September) and the autumnal equinox day, producing what is called Silver Week. This tool counts it as a closed day under “citizens’ holiday”.
Are holidays more than a year ahead displayed correctly?: Holidays with fixed dates and Happy Monday holidays can be calculated correctly any number of years ahead. However, the spring and autumn equinox days are officially decided in the official gazette each February for the following year, so later years use estimated dates from astronomical calculation. Years that include an estimate are marked on the screen.
Can I get business days per month or scheduled working days per year?: Choose a year in the “Annual calendar” tab and the calendar days, business days, and closed days for January to December are listed in a table, along with yearly totals. The table can be copied as tab-separated text and pasted straight into a spreadsheet.
Does the number of days in a period include the start and end dates?: By default both ends are counted (“September 1 to September 30” is 30 days). If you want to exclude the first day, as in “counting from ◯”, or count only up to the day before the closing date, switch the setting under “How to count days”.
Can bank business days be counted in the same way?: Banks are closed on weekends and holidays plus December 31 to January 3, so you get close by using the “Weekends and holidays off” setting, turning on “Treat the New Year break (12/29–1/3) as closed”, and removing December 29–30 from the additional closed days. However, when a transfer arrives differs by financial institution and service, so follow the recipient’s notice for the final check.
Can I share the conditions I calculated with someone else?: Press “Copy link to these conditions” at the bottom of the screen and a URL containing the dates and numbers is copied. Whoever opens the link sees the same conditions already filled in. The results themselves can be copied as text with the copy button.

Special Thanks

SOLO GUILD | サービス作るAIエンジニア

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