INTRODUCTION & SHORT MANUAL
Japanese Era, Age & School Year Tools
Japanese era years, exact age, and school grade — without second-guessing.
Enter a date of birth and get the Japanese era year, the exact age on any reference date, the school grade, and the standard entrance and graduation years. Everything is calculated inside your browser.
Open the service Opens a separate site (a subdomain)
- Service URL
- wareki.rewrite-co.com
- Languages
- Japanese only (the tool covers Japanese era names and the Japanese school system)
- Pricing
- Free. Every calculator and reference table is free, and no account is needed.
- Who it is for
- Anyone filling in a Japanese form that asks for an era year, checking a family member’s age, working out a child’s school grade, or tidying up the dates on a Japanese résumé.
About this service
Which western year is Showa 64? Is “Heisei 31, May 1” a real date? Which grade does a child born on 1 April belong to? These are all answerable, but they are the kind of question that stops you in your tracks with a form in front of you. This tool answers them on the spot.
Era boundaries are decided by the full date, not the year alone. The eras changed partway through 1912, 1926, 1989 and 2019, so a year on its own is ambiguous. Dates that never existed — Heisei 31 May 1, Reiwa 1 April 30 — are rejected with the reason and the correct notation.
School grades follow the statute step by step: enrolment begins at the first 1 April on or after the day after the child “reaches the age of six”, and that day is legally the day before the sixth birthday. Because the tool implements this procedure rather than a shortcut, the 1 April / 2 April split, leap-day births and early-year births all come out right without special cases.
Getting started
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Pick the calculation
From the top page choose western-to-era, era-to-western, age, school grade and year, entrance and graduation years, or fiscal-year conversion. No sign-up.
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Enter a date
Results update as you type; there is no submit button. Full-width digits and forms such as “令和8年8月9日” or “S50.4.2” are accepted as they are.
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Read and copy the result
Western and Japanese era dates are shown side by side. “Copy result” gives you text you can paste straight into a document.
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Save on your device if you want
Age, school grade and entrance/graduation results can be saved with a free-form label such as “self” or “child 1”. They are stored only in this browser.
Pricing and cancellation
The tool is free. Era conversion both ways, age calculation, school grade and year, entrance and graduation years, fiscal-year conversion, the reference tables and copying results are all included at no cost. No account, no login, no advertising.
A Standard edition (JP ¥1,980, tax included, one-time purchase) would remove the on-device save limit and add multi-person labels, CSV export, JSON backup and a print view. The price is settled, but sales have not opened yet: there is no purchase button and no checkout page, so nothing can be charged today.
What to know before you start
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This is reference information, not an official determination
It does not replace decisions made by government offices, schools or employers. When filling in an application or an enrolment form, follow the instructions of whoever receives it and check the relevant certificate.
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Entrance and graduation years assume a standard path
Repeating a year, a gap year before university, skipping a grade, leave of absence, transfers, technical colleges, junior colleges, vocational schools, six-year programmes and changes to the system are not applied automatically. Course lengths and gap years can be adjusted by hand. For a résumé, confirm the dates on your graduation certificate.
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Dates of birth are never sent to a server
All calculation happens in your browser. Input is not placed in the URL and is not sent to analytics. Data is written to this browser only when you press save, and there is no field for a personal name.
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Dates before 3 December, Meiji 5 use the old calendar
Strict day-level conversion covers 1 January 1873 (Meiji 6, 1 January) onwards. Japan used the Tenpō lunisolar calendar before that, so months and days do not line up; earlier dates are shown as a year-level reference only.
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Future era names are never guessed
A new era is set by cabinet order only when the throne passes to a new emperor. It will be added once that order is published and the source has been checked.
Frequently asked questions
- Do I need an account?
- No. Every calculator and every reference table works without signing up or logging in.
- Why do 1 April and 2 April births end up in different school years?
- Enrolment starts at the first 1 April on or after the day following the day the child reaches the age of six (School Education Act, Article 17(1)), and that day is legally the day before the sixth birthday. A child born on 1 April reaches six on 31 March, so the very next day — 1 April — begins their school year. A child born on 2 April waits a further year.
- Can I write “Heisei 31, May 1”?
- That date does not exist. Heisei ended on 30 April 2019 and Reiwa 1 began on 1 May. The tool rejects it with an explanation and shows the correct notation.
- When does someone born on 29 February age in a common year?
- Legally the year completes at the end of 28 February (Civil Code, Article 143(2), proviso). In everyday usage the new age starts on 1 March. The tool shows both.
- Does it work with JavaScript disabled?
- The reference tables do. All four — era years, ages, entrance and graduation years, and school years — are generated as static HTML in advance. The calculators need JavaScript because they compute inside the browser.
- Can I move saved entries to another device?
- Export a JSON backup and import it on the other device. The file contains dates of birth, so store and transfer it carefully.
This page explains how the service is used. Where it differs from the Terms of Service or the refund policy, those documents apply.
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