Gera Tools

Japanese Era Converter (Gengō / 和暦)

Convert between Gregorian dates and Japanese era years (Reiwa, Heisei…).

Free Japanese era (Gengō / 元号) converter. Convert any Gregorian date to the Japanese era name and year (Reiwa, Heisei, Shōwa, Taishō, Meiji) and back. Privacy-first and runs entirely in your browser; nothing is sent anywhere. It runs free in your browser on Gera Tools, with nothing uploaded.

Last updated Source: Gera Tools

How is the Japanese era year calculated?

Each modern era begins on an exact Gregorian date — Reiwa on 1 May 2019, Heisei on 8 January 1989, Shōwa on 25 December 1926, Taishō on 30 July 1912 and Meiji on 23 October 1868. The era year equals the Gregorian year minus the era's start year plus one, so the first year of an era is year 1 (Gannen / 元年).

Japanese era converter

Japan dates documents, coins and official forms using the Japanese era system (Gengō / 元号), where years are counted from the start of each emperor’s era rather than continuously. This converter translates between ordinary Gregorian dates and wareki (和暦) era years, covering the five modern eras — Reiwa, Heisei, Shōwa, Taishō and Meiji. It is useful for reading Japanese forms, visa paperwork, birth certificates and historical records.

How it works

Each modern era has one fixed Gregorian start date:

EraKanjiGregorian start
Meiji明治23 October 1868
Taishō大正30 July 1912
Shōwa昭和25 December 1926
Heisei平成8 January 1989
Reiwa令和1 May 2019

To convert a Gregorian date, the tool finds the latest era whose start date is on or before that date (comparing year, month and day), then computes:

era year = Gregorian year − era start year + 1

The first year of any era is year 1, written Gannen (元年). Converting the other way, the Gregorian year is era start year + era year − 1.

Example

Take 28 May 2026. The latest era beginning on or before that date is Reiwa (started 1 May 2019). The era year is 2026 − 2019 + 1 = 8, so the result is 令和8 (Reiwa 8). Going back the other way, Reiwa 8 maps to 2019 + 8 − 1 = 2026.

Where era dates appear in real life

Understanding which era a year falls in matters in several practical contexts:

  • Residence and visa forms — Japanese immigration and residency forms often print a wareki year field. Knowing that your birth year of 1990, for example, falls in Heisei 2 prevents mistakes.
  • Japanese driver’s licences and ID documents — expiry dates and date of birth are printed in wareki; a Shōwa birth year simply means the person was born between 1926 and 1989.
  • Bank and contract documents — many Japanese banks and notaries date agreements in wareki as a matter of custom, even when the Gregorian date is also present.
  • Historical records and literature — anything referencing Shōwa 20 (1945) or Heisei 3 (1991) requires quick mental arithmetic to place in context; this converter eliminates that step.

Transition days and the Gannen convention

A day that falls exactly on the start of an era belongs to the new era — so 8 January 1989 is Heisei 1 (Gannen), and 7 January 1989 is still Shōwa 64. Official documents write the first year of any era as 元年 (Gannen) rather than 一年 (ichi-nen), a convention this tool follows. If you encounter a document dated “平成元年” that is 1989 in Gregorian.

It is privacy-first: every calculation happens locally in your browser and nothing is ever sent anywhere.