Japanese Era Converter Compared: Reiwa and Dates

A Japanese era converter turns a year such as Reiwa 8 into a Western year, or a Western date into an era date. The tools differ in what they show next to the result: year charts, gannen notes and era lists.

Which Japanese calendar converter fits your date lookup?

Pick by the job: a one-off lookup, a resume or form, or many dates. The comparison below covers what each tool's own page offers.

For a one-off lookup, any of the year converters below is enough. For a resume or a form, the useful features are a year chart and a clear note on the year when an era changes. For many dates, a spreadsheet or script is the safer route.

Era names, gannen and year boundaries to check first

Japan has five modern eras: Meiji, Taisho, Showa, Heisei and Reiwa. The 256-tools page lists these five.

Gannen means the first year of an era. Written as a number, it is year 1, so Reiwa gannen is Reiwa 1.

The year 2019 belongs to two eras. It is Heisei 31 until April 30, 2019, and Reiwa year 1 from May 1, 2019. For 2019, the year alone doesn't tell you the era, so a converter needs the exact date.

How seven Japanese year and date converters compare

The seven tools share one job but offer different extras. The table lists what each page shows.

Year converters with a Reiwa year chart

japancalc.com, 256-tools.com and waza.tools are built around entering a year and reading the converted year. They suit a reader who has a single year to check.

The japancalc page lists a Reiwa year chart as a quick reference. On waza.tools, you enter an era or Western year, read the result and copy it. The 256-tools page converts between Reiwa or Heisei years and Western years, in both directions.

Date converters that handle gannen and timezones

time.now goes further than a year lookup, and 256-tools.com also explains era boundaries and gannen. Both suit a reader who needs more than a year.

time.now accepts a date and a timezone, converts in either direction, and shows era details. It also explains gannen and handles invalid dates. 256-tools.com has FAQ entries on era boundaries and on gannen as year 1.

Era list and calendar pages for resumes

hoothin, rirekishobuilder and digrart put reference material next to the converter. They suit a reader who wants background on the calendar.

The hoothin page gives a conversion table with a list of eras. The rirekishobuilder page explains the gengo (era name) system and the eras it supports. The digrart page adds a glossary, use cases and related tools such as an age and school year calculator.

Calendar and date choices for forms, resumes and bulk work

For forms and reference tables, our pick is the sakuttoAI era converter. The link sits below the table.

Bulk work is the one job with no tool in this comparison. Converting a column of dates means formulas or code.

Reiwa year and gannen results to double-check

Check three things before you copy a converted date into a document. Each one can change the era or the year in the result.

• The 2019 changeover: Heisei 31 ends on April 30, 2019, and Reiwa 1 starts on May 1, 2019.
• Gannen: a first year should appear as year 1 in the result.
• The era in the source: confirm whether the source document says Heisei or Reiwa before converting.

Check any doubtful result against the Cabinet Office page on era names (gengo). Treat a converter's answer as a draft until it matches.

Summary

The right Japanese era converter depends on the job. Use a year chart for a one-year lookup, a date converter such as time.now for edge cases, and the sakuttoAI era converter for forms and reference tables. For many dates, switch to a spreadsheet or script.