1. Identify the era from the exact date
Do not choose an era from the Western year alone when a date is near a transition. Japan’s current era, Reiwa, began on May 1, 2019; the first four months of 2019 are still Heisei 31.
令和元年 / 令和1年平成元年 / 平成1年昭和元年 / 昭和1年2. Use the era-year formula
After confirming the date falls inside the era, subtract the number below:
- Reiwa: Western year − 2018.
- Heisei: Western year − 1988.
- Showa: Western year − 1925.
The formula gives 1 for the first year. It does not replace the boundary check: January 2019 calculates to Reiwa 1 mathematically, but Reiwa had not begun, so that date is Heisei 31.
3. Work through common examples
令和8年8月18日令和元年5月1日平成31年4月30日平成元年1月8日昭和64年1月7日4. Enter the result on a Japanese form
A form labelled 和暦 expects an era date. Select 令和, 平成, or 昭和, then enter the era year, month, and day in their separate boxes. A field labelled 西暦 expects the four-digit Western year instead.
Some forms display R8.8.18, while others require 令和8年8月18日. Use the full name unless the form provides an abbreviation, and enter year 1 if the field accepts numbers only instead of 元.
5. Avoid era-conversion mistakes
- Assuming every era started on January 1.
- Using the Reiwa formula for January through April 2019.
- Adding the era’s first Western year instead of subtracting the offset.
- Writing a two-digit Western year where an era year is requested.
- Using 元 in a numeric-only input or an abbreviation the form does not list.
Frequently asked questions
What Japanese era is 2026?
A date in 2026 is Reiwa 8, written 令和8年. The calculation is 2026 − 2018 = 8.
Was all of 2019 Reiwa 1?
No. Heisei 31 continued through April 30, 2019. Reiwa 1 began on May 1, 2019, so the exact month and day matter.
What does 元年 mean in a Japanese date?
元年 (gannen) means the first year of an era. 令和元年 and 令和1年 both refer to Reiwa 1, which began May 1, 2019.
Can I use R, H, and S on Japanese forms?
Only when the form uses or permits abbreviations. R means Reiwa, H means Heisei, and S means Showa; otherwise write the full era name or choose it from the form’s selector.
Primary sources
We reviewed these first-party references on August 18, 2026. Always follow the instructions on the form you are completing.