Japanese Age Calculator
数え年 · 元号 · Imperial Era Year
Find your Japanese Kazoedoshi age, your Imperial Era year (Reiwa, Heisei, Showa) and a full comparison with your international age — instantly and free.
How to Use the Japanese Age Calculator
Get your complete Japanese age result — Kazoedoshi traditional age, Imperial Era birth year, current era year, and international comparison — in three quick steps.
What Is Kazoedoshi (数え年)?
Kazoedoshi (数え年) — literally meaning "counted age" — is the traditional Japanese age system. Like Korean traditional age, it follows two rules that differ fundamentally from the international standard used in everyday modern Japan.
Rule 1 — Everyone Is Born at Age 1
In Kazoedoshi, a newborn is considered 1 year old from the moment of birth. The year spent developing in the womb is counted as the first year of life — so birth marks the completion of year one, not the beginning of year zero.
Rule 2 — Everyone Ages on January 1st
One year is added on January 1st of every new calendar year — not on the individual's birthday. A baby born on December 31st becomes Kazoedoshi age 2 the very next morning. This means the gap between Kazoedoshi and international age is always exactly 1 or 2 years — never 0 or more than 2.
"Kazoedoshi is rarely used in everyday life in modern Japan — but it still appears in traditional ceremonies, some Buddhist rituals, Shichi-Go-San (七五三) celebrations and certain formal occasions tied to Japanese cultural heritage."
満年齢 (Man-nenrei) — The Modern Japanese Age
Modern Japan uses 満年齢 (man-nenrei) — the international age standard — for virtually all official, legal, medical and everyday purposes. Man-nenrei starts at 0 at birth and adds 1 on each birthday, identical to Gregorian age. The Japanese government officially adopted man-nenrei as the legal age standard in 1902, though Kazoedoshi persisted culturally for decades.
The Japanese Imperial Era System (元号 Gengo)
Japan uses a unique dual dating system — both the Western Gregorian year and the Imperial Era year (元号, Gengo) appear on official documents, calendars and government forms. The Imperial Era resets to year 1 whenever a new Emperor ascends the Chrysanthemum Throne.
Japan is the only country in the world that still officially uses an Imperial Era calendar system alongside the Gregorian calendar in modern governance. When you fill in a form at a Japanese government office, hospital or bank, you are often required to give your birth year in both Gregorian and era year format.
| Era Name | Japanese | Gregorian Period | Emperor | Era Year Calculation |
|---|---|---|---|---|
| Reiwa | 令和 | May 1, 2019 – present | Naruhito | Gregorian − 2018 |
| Heisei | 平成 | Jan 8, 1989 – Apr 30, 2019 | Akihito | Gregorian − 1988 |
| Showa | 昭和 | Dec 25, 1926 – Jan 7, 1989 | Hirohito | Gregorian − 1925 |
| Taisho | 大正 | Jul 30, 1912 – Dec 24, 1926 | Yoshihito | Gregorian − 1911 |
| Meiji | 明治 | Oct 23, 1868 – Jul 29, 1912 | Mutsuhito | Gregorian − 1867 |
The Current Era — Reiwa (令和)
The current Japanese Imperial Era is Reiwa (令和), which began on May 1, 2019 when Emperor Naruhito ascended the throne. The name Reiwa is written with two kanji — 令 (rei, meaning "beautiful" or "auspicious") and 和 (wa, meaning "harmony") — and is officially translated as "Beautiful Harmony." In 2025, it is Reiwa 7 (令和7年).
Japanese Age vs Korean Age vs International Age
Kazoedoshi and Korean traditional age follow nearly identical logic — yet they developed independently in two different countries. Here is how all three systems compare.
| System | Starts At Birth | Adds 1 Year On | Used Today In |
|---|---|---|---|
| 🇯🇵 Kazoedoshi 数え年 | Age 1 | January 1st (Gregorian) | Traditional ceremonies, Buddhist rituals, Shichi-Go-San |
| 🇰🇷 Korean Age 세는나이 | Age 1 | January 1st (Gregorian) | Everyday conversation and social settings in Korea |
| 🇯🇵 Man-nenrei 満年齢 | Age 0 | Each birthday | All modern Japanese legal, official and everyday use |
| 🌍 International Age | Age 0 | Each birthday | Global standard — passports, visas, contracts |
Japanese Age Calculation Examples
Practical examples showing Kazoedoshi and Imperial Era year together. Current year: 2025 (Reiwa 7).
Where Japanese Age Systems Still Matter Today
Shichi-Go-San (七五三) — Ages 3, 5 and 7
Shichi-Go-San is one of Japan's most beloved children's festivals, celebrated every November 15. Children aged 3, 5 and 7 visit Shinto shrines in traditional dress to pray for health and good fortune. Historically, the ages were counted in Kazoedoshi — meaning a child who is 4 in international age might be celebrated at 5 in Kazoedoshi. Today most families use the international age, but older traditions still reference Kazoedoshi for this ceremony.
Kanreki (還暦) — The 60th Birthday Milestone
Kanreki (還暦) is Japan's traditional 60th birthday celebration — one of the most important age milestones in Japanese culture. At 60, a person completes one full cycle of the traditional 60-year zodiac calendar (the same Stem-Branch cycle used in Chinese astrology) and symbolically begins life anew. Kanreki is celebrated with a red vest (chanchanko) and red accessories. In Kazoedoshi, Kanreki is observed at age 61.
Imperial Era in Official Documents
Japanese official documents — including residence certificates (住民票), family registers (戸籍), driver's licences and certain government forms — use the Imperial Era year alongside the Gregorian year. A person born in 1985 has "昭和60年" (Showa 60) on their family register. A person born in 2000 has "平成12年" (Heisei 12). Knowing your era birth year is practically necessary when dealing with Japanese bureaucracy.
Other Asian Age System Calculators
Every Asian age tradition works differently. Explore all of them below.
Related Guides
Go deeper into age calculation methods — from manual formulas to Excel functions.