Japanese Era (Gengō) and Gregorian Date Conversion Guide
Japanese official documents, contracts, résumés, government forms, receipts, and warranties often use the Japanese era system (元号, gengō) alongside or instead of the Gregorian calendar. Questions like "What year AD is Heisei 31?" or "When exactly was Showa 64?" come up whenever you work with Japanese paperwork or historical records.
This converter takes a Gregorian date and calculates the correct Japanese era name and year, with options to show kanji notation, romanization, and abbreviation codes (R1, H31, S64). Because an era can change mid-year, knowing the exact month and day — not just the year — is essential for accuracy.
📌 Major Japanese eras at a glance
| Era | Romanization | Start date | Abbreviation examples |
|---|---|---|---|
| 令和 | Reiwa | 2019-05-01 | R1, R6 |
| 平成 | Heisei | 1989-01-08 | H1, H31 |
| 昭和 | Showa | 1926-12-25 | S1, S64 |
| 大正 | Taisho | 1912-07-30 | T1, T15 |
| 明治 | Meiji | 1868-01-25 | M1, M45 |
1. What is the Japanese era system?
The Japanese era system (元号, gengō) assigns a name to each imperial reign.
Dates are written as the era name followed by the year number within that era
— for example 令和6年, 平成31年, or 昭和64年.
This system is commonly used in Japanese paperwork and records,
including official forms, personal history documents, contracts, and older materials,
either on its own or alongside the Gregorian year.
For instance, 2019-05-01 is the first day of Reiwa and is written 令和元年5月1日.
The previous day, 2019-04-30, still falls in Heisei and is written 平成31年4月30日.
2. Why the same calendar year can belong to two different eras
A new era begins on a specific date, not at the start of a year, so looking up the year alone is not enough. In 2019, for example, April 30 is Heisei 31 and May 1 is Reiwa 1 (gannen).
2019-04-30→ 平成31年4月30日 / Heisei 312019-05-01→ 令和元年5月1日 / Reiwa 1 (gannen)1989-01-07→ 昭和64年1月7日 / Showa 641989-01-08→ 平成元年1月8日 / Heisei 1 (gannen)
Because a single day's difference can mean a different era, always enter the full date — month and day included — rather than the year alone.
3. What is gannen (元年)?
In Japanese convention, the first year of a new era is written 元年
(gannen, meaning "founding year") rather than 1年.
So the first year of Reiwa is officially 令和元年, not 令和1年,
though both are understood.
Toggle the Use gannen option to switch
between 元年 and 1年 notation.
Match the format required by your document or form.
4. Quick conversion formulas
For a rough mental calculation, add the following offset to the era year to get the Gregorian year. Keep in mind that transition years require checking the exact date.
- Reiwa (令和): era year + 2018 = Gregorian year
- Heisei (平成): era year + 1988 = Gregorian year
- Showa (昭和): era year + 1925 = Gregorian year
- Taisho (大正): era year + 1911 = Gregorian year
- Meiji (明治): era year + 1867 = Gregorian year
Example: Heisei 31 → 31 + 1988 = 2019. But note that only the portion of 2019 up to April 30 is Heisei 31; from May 1 it becomes Reiwa 1.
5. When you need Japanese era dates
- Résumés and job applications: date of birth and employment history are often written in era format on Japanese résumé forms (履歴書)
- Visa and government forms: Japanese official forms may require dates in era notation
- Contracts, real estate, and financial documents: contract dates or validity periods written in era format
- Receipts and warranties: purchase date or warranty period shown in Japanese era
- Translation and research: converting era dates in Japanese documents to Gregorian for reference
6. What are the abbreviation codes R1, H31, S64?
Japanese eras are often abbreviated using the initial letter of
their romanization followed by the year number.
Reiwa = R, Heisei = H, Showa = S,
Taisho = T, Meiji = M.
- 令和元年 →
R1 - 平成31年 →
H31 - 昭和64年 →
S64 - 大正15年 →
T15 - 明治45年 →
M45
These codes may appear on Japanese driver's licenses, insurance cards, and various official forms where space is limited.
🛑 Checklist before filling in a Japanese era date
- Have you entered the full date — month and day, not just the year?
- Is the date close to an era transition boundary?
- Does the form require gannen (元年) notation or the numeral 1?
- Which notation does the form expect — kanji, romanization, or abbreviation?
- For official submissions, have you confirmed the venue's date format requirements?
FAQ
Q. What Japanese era year is today?
Click the Today button to instantly see the current date in Japanese era notation.
Q. Are Heisei 31 and Reiwa 1 both in 2019?
Yes — both fall within the Gregorian year 2019, but they cover different date ranges. Heisei 31 runs through April 30, 2019; Reiwa 1 begins on May 1, 2019.
Q. Why is Showa 64 so short?
Showa 64 covers only January 1–7, 1989. Heisei 1 began on January 8, 1989.
Q. Why does Meiji 1 start on January 25, 1868?
The official proclamation date and the retroactively applied start date of Meiji differ.
This tool uses 1868-01-25 as the Meiji 1 start date, based on the retroactively applied reference date.
Q. Can I look up eras older than Meiji?
This tool focuses on the modern eras from Meiji onward. Older eras such as Taika (大化) are available as historical reference start dates, but for ancient dates or academic work, consult the original source's calendar system.