Wareki to Seireki: Conversion Basics & Era Chart (Reiwa, Heisei, Showa)
Clear up "what year is Reiwa?" and "what is Showa 60 in CE?" with simple add-on numbers, a Reiwa/Heisei/Showa chart, era-change cautions, and tips for using each system on documents.
Japanese paperwork constantly mixes two ways of writing the year: the Japanese era system (wareki), such as "Reiwa 7," and the Western calendar (seireki), such as "2025." Most people use them by feel, but freeze when asked "What Western year does Reiwa start from?" or "What year is Showa 60?" This guide covers the basic conversion rules, quick mental-math tips, a conversion table for Reiwa, Heisei, and Showa, how to choose between them on documents, and how it all ties into age calculation.
Wareki vs. seireki basics
The Western calendar (seireki) is the global standard, numbering years continuously (2025, 2026, and so on). The Japanese era system (wareki) combines a gengo (era name)—set in line with imperial reigns—with the number of years since that era began. "Reiwa 7" means the 7th year of the Reiwa era.
The main modern eras are Meiji, Taisho, Showa, Heisei, and Reiwa. Each has a starting Western year, which makes conversion easy. Reiwa began in 2019 (Reiwa 1), so adding 2018 to a Reiwa year gives the Western year, and subtracting 2018 reverses it.
Key point: To convert wareki to seireki, just add a fixed number for each era. Memorize those numbers and you can convert almost instantly in your head.
Reiwa / Heisei / Showa conversion table
Here are the three most-used eras with their start years and the number to add for conversion to the Western year. Add it to the wareki year to get seireki; subtract it from seireki to get the wareki year.
| Era | Start (CE) | End (CE) | Convert to CE |
|---|---|---|---|
| Showa | 1926 | 1989 | wareki + 1925 |
| Heisei | 1989 | 2019 | wareki + 1988 |
| Reiwa | 2019 | present | wareki + 2018 |
For example, Showa 60 = 60 + 1925 = 1985, Heisei 10 = 10 + 1988 = 1998, and Reiwa 7 = 7 + 2018 = 2025. Some common pairs:
- Reiwa 1 = Heisei 31 = 2019 (era changed on May 1)
- Reiwa 6 = 2024, Reiwa 7 = 2025, Reiwa 8 = 2026
- Heisei 1 = Showa 64 = 1989 (era changed on January 8)
- Showa 1 = Taisho 15 = 1926, Showa 50 = 1975
To convert many years at once, or if you are unsure, the Wareki-Seireki Converter handles both directions and gets the era boundaries right.
Watch the era-change years
The trickiest cases are the years an era changed. Because changes happen mid-year, a single Western year can contain two eras:
- 1989: Showa 64 through Jan 7, Heisei 1 from Jan 8.
- 2019: Heisei 31 through Apr 30, Reiwa 1 from May 1.
- 1926: Taisho 15 through Dec 24, Showa 1 from Dec 25.
So someone "born in 2019" is Heisei if born Jan–Apr and Reiwa from May on. When writing a birth date in wareki, check the full date to know which era applies.
Choosing wareki or seireki on documents
The required format usually depends on the document, and changing it yourself may cause rejection.
Documents that tend to use wareki
Government-issued papers (residence records, family registers, driver's licenses) and pension or insurance forms still often use wareki, sometimes with "Reiwa __ " pre-printed.
Documents that tend to use seireki
Applications to foreign-affiliated firms, overseas certificates, IT input forms, and international contracts default to the Western calendar to avoid confusion.
What about resumes?
On a resume, pick one system and stay consistent. Mixing them across education, work history, and qualifications makes your record hard to follow. If unspecified, either is fine; seireki suits foreign employers, wareki suits government roles.
Relationship with age and date calculation
Conversion ties closely to calculating ages and periods. If you only have a birth date in wareki, convert it to seireki first to reduce errors. To find the age of someone "born in Showa 55," convert to 1980, subtract from the current year, then adjust for whether the birthday has passed.
Full age is not simple subtraction—it shifts by one depending on whether the birthday has arrived that year. For accuracy, enter the date in the Age Calculator. To find the gap between two dates (years of service, contract length), use the Date Difference Calculator; convert wareki dates to seireki first.
Summary
Wareki-seireki conversion is easy once you know the add-on numbers (Showa +1925, Heisei +1988, Reiwa +2018), but watch the era-change years where the era shifts mid-year. Match the document's required format and keep resumes consistent. For bulk or exact conversion use the Wareki-Seireki Converter, and for ages or periods use the Age Calculator or Date Difference Calculator.
This article summarizes general conversions and document practices. Required formats vary by recipient, so always confirm official guidance for formal procedures.
FAQ
What Western year does Reiwa start from?
Reiwa began on May 1, 2019 (Reiwa 1). Add 2018 to a Reiwa year to get the Western year—Reiwa 7 is 7 + 2018 = 2025. Subtract 2018 to go the other way.
What Western year is Showa 60?
For Showa, add 1925 to the wareki year, so Showa 60 is 60 + 1925 = 1985. Likewise Showa 50 is 1975 and Showa 1 is 1926.
Which era do I use for an era-change year?
Era changes happen mid-year, so it depends on the date. In 2019, dates through April 30 are Heisei 31 and from May 1 are Reiwa 1. For date-sensitive documents, check the full date.
Should a resume use wareki or seireki?
Either is fine, but never mix them—stay consistent across education, work, and qualifications. If unspecified, seireki suits foreign employers and wareki suits government roles.
How do I calculate age from a wareki birth date?
Convert the birth date to the Western year first, subtract from the current year, then adjust by one depending on whether the birthday has passed. For accuracy, enter the converted date into an age calculator.