Business Day Calculator
Calculate a date a given number of business days after a start date, or count the business days between two dates — excluding weekends and Japanese public holidays. You can also toggle whether Saturdays count as business days.
How This Tool Defines a "Business Day"
| Monday–Friday | Counted as a business day unless it is a holiday |
|---|---|
| Saturday | Not counted as a business day by default (counted if "Count Saturdays as Business Days" is enabled) |
| Japanese Public Holidays & Substitute Holidays | Always excluded from business days (uses the same data as our sister Holiday List Calendar) |
| Supported Holiday Data Range | 2017–2027 |
Tips
- Handy for checking a payment deadline like "net 30 business days" on an invoice, or a delivery/submission due date. Just set the start date to the invoice or order date and enter the number of business days to see the actual due date.
- The mode that counts business days between two dates is useful for estimating workload on a business-day basis, or checking how many working days a project actually spans.
- If Saturdays count as working days in your industry (retail, some service businesses, etc.), enable "Count Saturdays as Business Days" before calculating.
- The holiday data shares the same source (published by Japan's Cabinet Office) as our sister tools, the Holiday List Calendar and the Holiday Checker, so substitute holidays are correctly reflected too.
Frequently Asked Questions
Side Note — There Is No Legal Definition of a "Business Day"
It may come as a surprise, but the term "business day" has no single, unified legal definition. Individual laws such as banking regulations or labor law each define "holidays" within their own context, but there is no general law that defines "business day" across the board — in practice, the common understanding of "a day excluding weekends and holidays" has simply formed through business and industry custom.
Expressions like "within X business days" in contracts and invoices are deliberately distinguished from calendar days. If a period were fixed at "within 30 calendar days," a long holiday stretch falling in between could drastically shrink the actual working time available — converting the period to business days is meant to smooth out the effect of holidays and weekends.
The financial industry also uses an even narrower concept: "bank business days," based on the days a bank's counters are open. This can lead to subtly different rules than the general "excluding weekends and holidays" definition — for example, in how brokerage closures or New Year's Eve (December 31 in Japan) are treated.