Japanese age: 数え年, imperial eras and 厄年
Japan reckons age two ways, dates years by imperial era as well as by the Gregorian year, and marks particular ages as needing care — each of which puts a number on a life that the other two would put somewhere else.
数え年 and 満年齢
| Count | How it is reckoned | Where it applies |
|---|---|---|
| 数え年 (kazoedoshi) | One at birth; everyone adds a year at New Year rather than on their birthday. | Shrine and temple observance — 厄年 and 七五三 are counted this way — and traditional contexts generally. |
| 満年齢 (mannenrei) | Years completed since birth; increments on the birthday. | Everything official and nearly all everyday speech. |
A statute passed in 1949 and in force from 1 January 1950 pressed 満年齢 into official and public use, and it took: unlike Korea, where the traditional count stayed in daily speech, Japan's traditional count now mostly appears where a tradition calls for it. Ask someone their age in Japan and you will be told their 満年齢.
Imperial eras
A Japanese year has two names: 2026 is also Reiwa 8. An era begins on the day the emperor accedes, which means the same Gregorian year is counted as the last year of one era and the first year of the next — 1989 is both Showa 64 and Heisei 1. The first year of an era is written 元年 (gannen) rather than 1年.
| Era | Began | Ended |
|---|---|---|
| Reiwa (令和) | current era | |
| Heisei (平成) | 30 April 2019 | |
| Showa (昭和) | 7 January 1989 | |
| Taisho (大正) | 24 December 1926 | |
| Meiji (明治) | 29 July 1912 |
Because an era boundary falls on a day rather than at a year end, two consecutive days can carry era years that look years apart:
| Gregorian date | Era year |
|---|---|
| 昭和64年 (Showa 64) | |
| 平成元年 (Heisei 1) | |
| 平成31年 (Heisei 31) | |
| 令和元年 (Reiwa 1) |
Where this stops
Era years are published here from 1 January 1873, when Japan adopted the Gregorian calendar. Before that the official calendar was lunisolar, and a Gregorian date does not map onto an era year without stating which conversion was used — so this site refuses rather than guessing. Meiji began in 1868 and appears in the table above, but era years are only computed from 1873 on.
Era start dates are the dates of accession, held as data in the same module the calculator reads, so the table above and any figure the calculator gives come from one list.
Prose last reviewed 2026-08-19.
Worked examples
Computed on 20 August 2026 in the Asia/Tokyo zone, at build time.
| Birthdate | Era year of birth | 数え年 | 満年齢 |
|---|---|---|---|
| Born 7 January 1989 — the last day of Showa | 昭和64年 (Showa 64) | 38 | 37 |
| Born 8 January 1989 — the first day of Heisei | 平成元年 (Heisei 1) | 38 | 37 |
| Born 1 May 2019 — the first day of Reiwa | 令和元年 (Reiwa 1) | 8 | 7 |
厄年 — the years that call for care
Certain ages are traditionally held to be unsettled ones, and are marked at Shinto shrines with 厄除け (yakuyoke), a prayer for protection. They are counted in 数え年, so someone reaches their 厄年 in the calendar year they turn one less than the number below. The year before is 前厄 (mae-yaku) and the year after 後厄 (ato-yaku); people commonly observe all three.
| Whose | 本厄 (数え年) | 前厄 | 後厄 | Note |
|---|---|---|---|---|
| Men — 本厄 at 25 | 25 | 24 | 26 | — |
| Men — 本厄 at 42 | 42 | 41 | 43 | 大厄 (dai-yaku), the most significant of the set |
| Men — 本厄 at 61 | 61 | 60 | 62 | — |
| Women — 本厄 at 19 | 19 | 18 | 20 | — |
| Women — 本厄 at 33 | 33 | 32 | 34 | 大厄 (dai-yaku), the most significant of the set |
| Women — 本厄 at 37 | 37 | 36 | 38 | — |
| Women — 本厄 at 61 | 61 | 60 | 62 | — |
These are the ages observed at most shrines, and the list a Japanese calendar or shrine pamphlet will print. A particular shrine's reckoning can differ, and the custom is regional in places; where it matters, the shrine's own list is the one to follow. This site records the common list rather than adjudicating between them.
年祝い — the celebrations of a long life
A series of ages are marked with celebrations: 還暦 (kanreki) at the completion of the sixty-year stem-branch cycle, 古希 (koki) at 70, 喜寿 (kiju) at 77, 米寿 (beiju) at 88, and on to 白寿 at 99 and 百寿 at 100. Most of the names are wordplay on the numbers — the character 米 comes apart into 八十八, eighty-eight; the cursive form of 喜 reads as seventy-seven — and each carries its own colour and its own customs. 還暦 is marked with a red ちゃんちゃんこ, the vest of a newborn, because completing the cycle returns you to the year you were born in and, in a sense, to the beginning.
These are celebrations of having arrived, and they are joyful where they are held. This site names them as such rather than as a countdown, and does not publish life-expectancy figures or anything that would turn a milestone into a forecast.