Japan Generation Breakdown 2026: How Many Millennials, Gen Z, and Boomers?

By Marko Visic · Updated October 19, 2026

A UN projection for 1 July 2026 from World Population Prospects 2024 (medium variant).

In Japan, Baby Boomers are the largest generation: 29,715,349 people, 24.3% of the population.

See the population pyramid for Japan.

Gen Beta: 1,125,925 (0.9%)
Gen Alpha: 10,798,108 (8.8%)
Gen Z: 18,935,023 (15.5%)
Millennials: 20,792,967 (17.0%)
Gen X: 28,450,780 (23.2%)
Baby Boomers: 29,715,349 (24.3%)
Silent Generation: 12,372,514 (10.1%)
Greatest Generation: 237,065 (0.2%)

122,427,731

people on 1 July 2026

24.3%

Baby Boomers, the largest generation

15.5%

Gen Z share, the 2nd-lowest of the 194 countries

11,924,033

under 14 (Gen Alpha + Gen Beta)

12,609,579

aged 81+ (Silent + Greatest)

Generation Population Distribution - Japan

Gen Beta: 0.9%

Gen Alpha: 8.8%

Gen Z: 15.5%

Millennials: 17.0%

Gen X: 23.2%

Baby Boomers: 24.3%

Silent Generation: 10.1%

Greatest Generation: 0.2%

Generation Breakdown by Population - Japan

Total Population: 122,427,731

Generation	Birth Years	Age Range (2026)	Population	% of Total	Male	Female
Gen Beta	2025–2039	0–1 years	1,125,925	0.9%	576,170	549,755
Gen Alpha	2013–2024	2–13 years	10,798,108	8.8%	5,533,685	5,264,422
Gen Z	1997–2012	14–29 years	18,935,023	15.5%	9,692,732	9,242,291
Millennials	1981–1996	30–45 years	20,792,967	17.0%	10,564,425	10,228,542
Gen X	1965–1980	46–61 years	28,450,780	23.2%	14,341,639	14,109,141
Baby Boomers	1946–1964	62–80 years	29,715,349	24.3%	14,263,400	15,451,949
Silent Generation	1928–1945	81–98 years	12,372,514	10.1%	4,651,041	7,721,473
Greatest Generation	before 1928	99+ years	237,065	0.2%	38,731	198,334
Total			122,427,731	100.0%	59,661,824	62,765,908

Projected population on 1 July 2026, UN World Population Prospects 2024 (medium variant). Generation definitions: Pew Research Center (Greatest Generation to Gen Z); McCrindle Research (Gen Alpha, Gen Beta).

Japan Generations: Frequently Asked Questions

Population on 1 July 2026, UN World Population Prospects 2024 (medium variant).

What is the largest generation in Japan?

Baby Boomers are the largest generation in Japan, with 29,715,349 people (24.3%).

How many Gen Z, Millennials and Baby Boomers are in Japan?

Japan has 18,935,023 Gen Z, 20,792,967 Millennials and 29,715,349 Baby Boomers.

What share of Japan is Gen Z, and how does it rank?

Gen Z is 15.5% of Japan, the 2nd-lowest Gen Z share of the 194 countries.

How do the youngest and oldest generations compare in Japan?

The youngest generations, Gen Alpha and Gen Beta, together number 11,924,033 in Japan, versus 12,609,579 in the oldest two, the Silent and Greatest generations.

How does the largest generation in Japan compare with the world?

Baby Boomers are 24.3% of Japan, compared with 11.8% worldwide.

Explore Generation Data by Country

Other countries in Asia. See all 194 countries →