Japanese Era to Gregorian Year Conversion:
Reiwa, Heisei and Showa Explained

What is a Japanese era, and how does it differ from the Gregorian year?

Japan uses two ways of writing years side by side. The Gregorian (Western) year, such as 2026, counts from a single worldwide starting point. The Japanese era system (gengō, 元号) counts years from the start of an era name such as Reiwa. The first year of an era is written gannen (元年, "year one"), so 2019 was the first year of Reiwa.

Under the Era Name Act, the era name is set by cabinet order and changes only when a new emperor accedes (Cabinet Office). Since the Meiji era, each emperor has had one era name (issei ichigen, 一世一元) (National Archives of Japan). The five eras in modern use are Meiji (M), Taisho (T), Showa (S), Heisei (H) and Reiwa (R); the letters are the common abbreviations, as in "R8" or "H30".

Era year to Gregorian year: formulas and examples

Each formula adds a fixed number to the era year. The number is the Gregorian year in which the era began, minus one (Reiwa began in 2019, so 2019 − 1 = 2018).

To go the other way, subtract:

• Reiwa: Gregorian year − 2018 (2026 − 2018 = Reiwa 8)
• Heisei: Gregorian year − 1988
• Showa: Gregorian year − 1925
• Taisho: Gregorian year − 1911
• Meiji: Gregorian year − 1867

These formulas give the year only. In 1912, 1926, 1989 and 2019 two eras share one Gregorian year, so you also have to check the month and day (see Years when the era changed). The Ministry of Health, Labour and Welfare publishes a Japanese era / Gregorian year table that matches these formulas, for example Reiwa 8 = 2026 and Reiwa 12 = 2030.

Reiwa mental-math trick: add the last two digits

It works because the last two digits of a year from 2020 to 2029 are "2" and a digit d, and (20 + d) − 18 = 2 + d. This shortcut is meant for Reiwa 2 to 9 (2020–2027), where the Reiwa year has one digit. 2019 is a special case (Reiwa began on May 1, 2019), and from 2028 on, use the basic formula: Gregorian year − 2018.

Heisei mental-math method: add 12

For years from 2000 to 2018, add 12 to the last two digits of the Gregorian year to get the Heisei year.

• 2010 → 10 + 12 = 22 → Heisei 22
• 2015 → 15 + 12 = 27 → Heisei 27
• 2018 → 18 + 12 = 30 → Heisei 30

Years when the era changed

• Until January 7, 1989: Showa 64
• From January 8, 1989: Heisei 1 (gannen)
• Until April 30, 2019: Heisei 31
• From May 1, 2019: Reiwa 1 (gannen)

The Heisei cabinet order was issued on January 7, 1989 and took effect the next day, January 8 (Cabinet Office, National Diet Library). The Reiwa order took effect on the day after April 30, 2019, that is, May 1 (Cabinet Office, National Diet Library). So 2019 is both Heisei 31 (January 1 – April 30) and Reiwa 1 (May 1 – December 31), and 1989 is both Showa 64 and Heisei 1.

Each era runs until the day before the next one begins. This article converts years; for exact dates in the Meiji era, use a dedicated conversion table.

Where you will meet Japanese era years

You do not need to read Japanese to run into era years. Typical places:

• Forms and certificates issued in Japan: dates are often printed in era years, for example "R8.1.15" for January 15, 2026.
• Birth dates on older documents: someone born in 1985 may be listed as born in "Showa 60".
• Web forms and date pickers: some Japanese sites ask for the era and the era year instead of the Gregorian year.
• History, museums and books: events are often dated by era, such as "Meiji 35" for 1902.
• Data exports from Japanese systems: a column of dates may mix era years and Gregorian years.

Tips: look for the era letter or kanji before the number (R, H, S, T, M, or 令和, 平成, 昭和, 大正, 明治); "元年" means year 1; and in 1912, 1926, 1989 and 2019 check the month and day. When you are asked for a date and the form accepts either, the Gregorian date avoids the conversion.

Related guides: What is ISO 8601? · Is 08/09/2026 August 9 or September 8? · What is the yyyyMMdd format? · World Date Formats and Calendar Systems Explained

Frequently Asked Questions

References

• Cabinet Office of Japan: About era names (元号について) — Era Name Act and the cabinet orders for Reiwa and Heisei, with their effective dates
• Ministry of Health, Labour and Welfare: Japanese era / Gregorian year table (和暦西暦早見表) — era-year to Gregorian-year pairs, for example Reiwa 8 = 2026
• National Archives of Japan: Meiji 1 (1868), one era name per emperor — the Meiji era change and the one-era-per-emperor system
• National Archives of Japan: Meiji 45 (1912), change to Taisho — Taisho began on July 30, 1912
• National Archives of Japan: Taisho 15 (1926), change to Showa — Showa began on December 25, 1926
• National Diet Library Reference Collaboration Database: start dates of Showa 1 and Heisei 1 — Heisei took effect on January 8, 1989
• National Diet Library Reference Collaboration Database: when Reiwa 1 began — Reiwa began on May 1, 2019