Japanese Era Converter

How to Use the Japanese Era Converter

1. 1. Choose the direction. Gregorian → Japanese era takes a Western date; Japanese era → Gregorian takes an era, a year and, optionally, a month and day.
2. 2. Enter the date. Month and day are optional. With only a year, the tool lists every era that year belongs to and the days each covers; with a full date, it gives the exact era date.
3. 3. Pick how to write the first year. Japanese documents write the first year of an era as 元年 (gannen). Tick the box for 元 or clear it for the number 1.
4. 4. Copy the result. You get the date in kanji, in the compact form used on forms (R1.5.1), as a single square glyph (㋿1.5.1), in plain English and in ISO 8601, plus notes on any rule that applied.

The Five Modern Eras and Their Start Dates

Since the Meiji period Japan has followed the rule of one reign, one era name (一世一元): the era changes only when an emperor dies or abdicates. The five modern eras began on the dates below, and each ended the day before the next began.

How the Era Year Is Counted

The first year of an era (gannen, 元年) begins on the day the era starts and ends on 31 December. From the next 1 January each Gregorian year adds one to the era year. That makes conversion simple arithmetic: era year = Gregorian year − offset, and the offsets are 1867 for Meiji, 1911 for Taishō, 1925 for Shōwa, 1988 for Heisei and 2018 for Reiwa. The year 2000 is Heisei 12 (2000 − 1988), and a Reiwa year is the Gregorian year minus 2018.

Because the new era starts partway through a Gregorian year, four Gregorian years belong to two eras: 1912 is Meiji 45 until 29 July and Taishō 1 from 30 July; 1926 is Taishō 15 and Shōwa 1; 1989 is Shōwa 64 for its first seven days and Heisei 1 for the rest; and 2019 is Heisei 31 until 30 April and Reiwa 1 from 1 May. The year-only mode lists them both. The last year of a finished era is short too: Shōwa 1 lasted just seven days.

Before 1873: The Lunisolar Caveat

Japan used a lunisolar calendar until the end of 1872. The government then adopted the Gregorian calendar: the day after 2 December of Meiji 5 became 1 January of Meiji 6, that is 1 January 1873. For dates from 1873 the era date and the Gregorian date line up exactly. For earlier dates a Gregorian date has no exact twin, because the old year began in January or February and had months of its own. Meiji 1 is also defined retroactively: the era name took effect on 23 October 1868, but the year Keiō 4 was renamed Meiji 1 retroactive to its New Year. The tool starts the era on the day the name took effect, counts Meiji 1 to 5 by subtracting 1867 from the Gregorian year, and marks every date before 1873 as approximate. For academic work on those years, convert from the lunisolar record instead.

Frequently Asked Questions

What is the current Japanese era?

Reiwa (令和), which began on 1 May 2019 when Emperor Naruhito acceded to the throne. A Reiwa year is the Gregorian year minus 2018, so 1 May 2019 to 31 December 2019 is Reiwa 1 and 2020 is Reiwa 2.

What is gannen (元年)?

The word for the first year of an era. Documents write 令和元年 instead of 令和1年. The first year runs from the start date of the era to 31 December, so Heisei 1 is 8 January to 31 December 1989. Both 元 and 1 are understood.

How do I convert a Heisei year to the Gregorian calendar?

Add 1988: Heisei 12 is 2000, Heisei 31 is 2019. Dates from 1 January to 7 January 1989 are Shōwa 64, so Heisei 1 starts on 8 January 1989. For Shōwa add 1925, for Taishō 1911, for Meiji 1867 and for Reiwa 2018.

Why do 1989 and 2019 have two eras?

Because an era changes on the day after an emperor's reign ends, not on 1 January. The Shōwa Emperor died on 7 January 1989, so the first week of 1989 is Shōwa 64. The Heisei era ended with the abdication on 30 April 2019 and Reiwa began on 1 May.

What came before Meiji?

The Edo-period era Keiō (慶応), among many earlier ones. Before Meiji, eras changed for reasons such as disasters or auspicious omens and could be short. The rule of one era name for each reign began with Meiji. This tool does not convert dates before 23 October 1868.

What do R1.5.1 and ㋿ mean?

R1.5.1 is the compact form used on Japanese forms and filenames: the era letter (M, T, S, H or R), the year, the month and the day, here Reiwa 1, 1 May. ㋿ is a single Unicode character for Reiwa (U+32FF); there are matching glyphs for Meiji (㍾), Taishō (㍽), Shōwa (㍼) and Heisei (㍻).

Are pre-1873 dates accurate?

Only approximately. Japan's calendar before 1873 was lunisolar, so a Gregorian date in 1868 to 1872 may fall in the previous or next lunar year. The tool uses the Gregorian year minus 1867 and says so, but a historian needs the original lunar date.