Japanese Era & Chinese Zodiac Calculator

What is the Era & Zodiac Calculator?

This calculator converts between Gregorian (Common Era) years and Japanese imperial eras (wareki), and also shows the Chinese zodiac sign for the same year. The Japanese era system is Japan's own way of counting years, with a new era name proclaimed for each emperor's reign. This tool covers Meiji, Taishō, Shōwa, Heisei and Reiwa. For example, 2025 CE is Reiwa 7, and its zodiac is Yi-Si — the Wood Snake. The zodiac shown here is the East Asian sexagenary cycle, formed by pairing the ten Heavenly Stems (Jiǎ, Yǐ, Bǐng…) with the twelve Earthly Branches (Rat, Ox, Tiger…). The cycle repeats every 60 years and underlies the familiar twelve animal signs used across China, Japan, Korea and Vietnam. Japanese documents, licences and diplomas often use era dates, so converting to and from the Western calendar is frequently needed.

How to use it

1. Choose "Gregorian → Era & Zodiac" and type the Gregorian year. Month and day are optional and only matter in a year when the era changed. 2. The result shows the Japanese era (e.g. Reiwa 7) plus the year's sexagenary sign and its zodiac animal. 3. Switch to "Japanese Era → Gregorian" to convert an era name and era year back to a Gregorian year. 4. Use the reference table below to see the start date of each era on the Gregorian calendar.

How the calculation works

Conversion to a Japanese era uses each era's official start date mapped to its Gregorian year. In a year when the era changed, the result depends on whether the date falls before or after the start date, so adding the month and day makes it precise (year 1 of an era is its first year). The zodiac is derived from the Gregorian year. The Heavenly Stem is (year − 4) mod 10 and the Earthly Branch is (year − 4) mod 12. There are 60 stem-branch combinations, completing a full cycle every 60 years. For example, 1984 and 2044 are both Jiǎ-Zi (No. 1 of the cycle).

Reading your result

Era "year 1" (gannen) means the first year of that era — for instance Reiwa 1 is 2019. In a transition year, the same Gregorian year can map to two different eras depending on the date (Japan switched from Heisei to Reiwa on 1 May 2019). The zodiac is written as stem + branch, and each branch carries a familiar animal (Rat, Ox, Tiger…). Your birth-year animal is a handy clue to age, and at 60 you return to the stem-branch of your birth year — the "kanreki" milestone celebrated in Japan.

Frequently asked questions