Business days calculator (Japan)
Payment terms, delivery promises and legal deadlines in Japan are written as “within N business days” (〇営業日以内). This counts them the way Japanese companies do: Saturdays, Sundays and every national holiday off, plus whatever closures you add.
- Runs entirely in your browser
- Works offline
- No upload
- No sign-up
- No watermark
Loading the tool…
How it works
- Choose “date ± business days” or “business days between two dates”.
- Enter the date (or the two dates) and the number of business days. Use a negative number for “N business days before”.
- Adjust the days off if your week is different, tick year-end or Obon, and add any other closures, one per line. The result updates as you type.
Why nothing is uploaded
Every operation on this page is done by code running inside your browser tab, using the same engine that renders web pages. The file is read from disk into your tab’s memory, transformed there, and written back out as a download. It is never sent anywhere — not to us, not to a third party.
Verify it yourself
- Open your browser’s developer tools (F12) and select the Network tab.
- Load your file and run the tool.
- The only requests you will see fetch the tool’s own code — and, for a few heavy tools, their open-source engine (also from this site) or an AI model from Hugging Face — plus one small page-view ping to loreatec.jp (page address and title, nothing more). None of them carry your file.
Frequently asked questions
Which holidays are included?
Every national holiday under the Public Holiday Law from 1980 to 2099: the fixed dates, the “Happy Monday” ones, both equinoxes, substitute holidays when a holiday falls on a Sunday, and the in-between “citizens’ holiday” that appears in some Septembers. The one-off holidays are there too — 2019 (enthronement) and the Olympic shifts of 2020 and 2021.
Does “10 business days after” count the start date?
No, by default the count starts the next day, which is how Japanese deadlines (〇営業日後) are normally read: from a Monday, 3 business days later is the Thursday. If your contract counts the start date as day one, tick the box and the start date counts when it is itself a business day.
Are the equinox dates certain?
For years already announced, yes. The government publishes the spring and autumn equinox holidays every February for the following year; later years use the standard astronomical formula, which has matched every announcement since 1980 but is still a prediction until published.
Is anything sent to a server?
No. The holiday rules are computed in the page itself and work offline. Your days off and closures are remembered in this browser only.