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How to Calculate Your Age from Birth Year | Japanese Era & Western Calendar Reference Table

age calculatorbirth yearreference tablewarekischool enrollment

"How old is someone born in Showa 60?" "What school year is a Heisei 5 child in?" Calculating age from a Japanese era birth year can be surprisingly tricky. This article explains how to do it and provides handy reference tables.

How to Calculate Age

The Basic Formula

Age this year = Current Western year − Birth Western year

If the birthday hasn't occurred yet this year, subtract 1.

Steps for Calculating Age from Wareki

  1. Convert the wareki birth year to seireki (Western calendar)
  2. Subtract the birth year from the current year

Example: Born in Heisei 5 → 1993 → 2026 − 1993 = 33 years old (after the 2026 birthday)

Free Tool

Japanese Era Converter

Convert between Western calendar years and Japanese era names (Reiwa, Heisei, Showa). Includes age calculator.

Try it now →

With sakutto's era converter, you can look up seireki, wareki, and age in a single reference table.

Age Reference Table (2026 Edition)

Born in Reiwa (2019–)

WarekiSeirekiAge in 2026
Reiwa 720250–1
Reiwa 620241–2
Reiwa 520232–3
Reiwa 420223–4
Reiwa 320214–5
Reiwa 220205–6
Reiwa Gannen20196–7

Born in Heisei (1989–2019)

WarekiSeirekiAge in 2026
Heisei 3020187–8
Heisei 25201312–13
Heisei 20200817–18
Heisei 15200322–23
Heisei 10199827–28
Heisei 5199332–33
Heisei Gannen198936–37

Born in Showa (1926–1989)

WarekiSeirekiAge in 2026
Showa 64198936–37
Showa 60198540–41
Showa 55198045–46
Showa 50197550–51
Showa 45197055–56
Showa 40196560–61
Showa 35196065–66
Showa 30195570–71
Showa 25195075–76
Showa 20194580–81

School Enrollment and Graduation Reference

Japan's School System

SchoolDurationEnrollment Month
Elementary school6 yearsApril of the year the child turns 6
Junior high school3 yearsApril of the year the child turns 12
High school3 yearsApril of the year the child turns 15
University4 yearsApril of the year the student turns 18

Enrollment Year Formula

Elementary school enrollment year = Birth year + 7 (if born on April 1, use +6)

Example: Born in 2000 → Elementary school enrollment: April 2007

EventFormula
Elementary school enrollmentBirth year + 7
Elementary school graduationBirth year + 13
Junior high enrollmentBirth year + 13
Junior high graduationBirth year + 16
High school enrollmentBirth year + 16
High school graduationBirth year + 19
University enrollmentBirth year + 19
University graduationBirth year + 23

Using This for Resumes

When filling in the education section of a Japanese resume (rirekisho), you need to list enrollment and graduation years in wareki.

Example (for someone born between April 2, 2000 and April 1, 2001):

YearEducation
Heisei 19 (April)Entered XX Elementary School
Heisei 25 (March)Graduated XX Elementary School
Heisei 25 (April)Entered XX Junior High School
Heisei 28 (March)Graduated XX Junior High School
Heisei 28 (April)Entered XX High School
Heisei 31 (March)Graduated XX High School
Heisei 31 (April)Entered XX University
Reiwa 5 (March)Graduated XX University

Free Tool

Japanese Era Converter

Convert between Western calendar years and Japanese era names (Reiwa, Heisei, Showa). Includes age calculator.

Try it now →

Frequently Asked Questions (FAQ)

What is the difference between "counting age" and "full age"?

Full age (man-nenrei) adds a year on each birthday and is the official system used in modern Japan. Counting age (kazoedoshi) counts the birth year as age 1 and adds a year every New Year's Day. Kazoedoshi is still used for events like Shichi-Go-San and yakudoshi.

Why is someone born on April 1 considered "early born"?

Under Japanese law (the Act on Calculation of Age), a person's age increments on the day before their birthday. So someone born April 1 turns a year older on March 31, placing them in the previous school year.

Should I use wareki or seireki for the education section of a resume?

Either is acceptable, but stay consistent throughout the document. Wareki is standard for Japanese companies; seireki is preferred by foreign-affiliated firms.

How do I calculate enrollment years if I took a gap year or repeated a grade?

For a gap year (ronin), add the number of gap years to the university enrollment year. For repeating a grade, add the extra years to the graduation year.

Summary

Calculating age or school enrollment years from a Japanese era birth year is quick and easy with sakutto's era converter reference table. Use it whenever you need to fill in a resume or complete official documents.

Free Tool

Japanese Era Converter

Convert between Western calendar years and Japanese era names (Reiwa, Heisei, Showa). Includes age calculator.

Try it now →

FAQ

Q. What is the difference between 'counting age' (kazoedoshi) and 'full age' (man-nenrei)?
Full age (man-nenrei) adds a year on each birthday and is the official system used in modern Japan. Counting age (kazoedoshi) counts the birth year as age 1 and adds a year every New Year's Day. Kazoedoshi is still used for events like Shichi-Go-San and yakudoshi.
Q. Why is someone born on April 1 considered 'early born' (hayaumare)?
Under Japanese law, a person's age increments on the day before their birthday. So someone born April 1 turns a year older on March 31, placing them in the previous school year.
Q. Should I use wareki or seireki for the education section of a resume?
Either is acceptable, but stay consistent throughout the document. Wareki is standard for Japanese companies; seireki is preferred by foreign-affiliated firms.
Q. How do I calculate enrollment years if I took a gap year or repeated a grade?
For a gap year (ronin), add the number of gap years to the university enrollment year. For repeating a grade, add the extra years to the graduation year.

Related Tools

Free Tool

Japanese Era Converter

Convert between Western calendar years and Japanese era names (Reiwa, Heisei, Showa). Includes age calculator.

Try it now

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