Japan has a population of approximately 123 million people as of 2025, making it the 12th most populous country in the world. That figure places Japan ahead of nations like Mexico and the Philippines, yet behind giants such as India, China, and the United States. What makes Japan's demographic story unusual is not its size but its direction: the country is shrinking, aging faster than any other major nation, and offering the rest of the developed world a preview of challenges to come.
How Many People Live in Japan?
Japan's population stands at roughly 123,000,000 in 2025, spread across four main islands — Honshu, Hokkaido, Kyushu, and Shikoku — and thousands of smaller ones. With a land area of about 378,000 km², this gives Japan a population density of around 325 people per square kilometre, one of the higher figures among large economies. Because much of Japan is mountainous and forested, the real population pressure is far greater than that average suggests: the vast majority of people are packed into narrow coastal plains and river valleys, leaving large stretches of the interior nearly empty.
The Japanese population is also overwhelmingly urban. More than 90% of residents live in cities and towns, and the country has steadily emptied its rural villages as younger generations move toward employment and education in major metropolitan regions.
A Population in Decline
Japan's population is now falling at an annual rate of about -0.53%, meaning the country loses on the order of 600,000 people each year — roughly the population of a mid-sized city vanishing annually. The total peaked at around 128 million in 2008 and has been declining ever since, making Japan one of the first major nations to enter sustained demographic contraction.
The root cause is an exceptionally low fertility rate, currently around 1.2 births per woman, far below the 2.1 needed to keep a population stable. Combined with very long life expectancy, this produces a society where deaths consistently outnumber births. Government projections suggest Japan could fall to roughly 104 million people by 2050 and to about 75 million by 2100 if current trends hold. Successive governments have introduced childcare subsidies, parental leave, and family incentives, but none has reversed the underlying trend.
The World's Oldest Society
Japan holds the distinction of being the world's most rapidly aging major nation. About 29% of the population is aged 65 or older — the highest proportion of any country on Earth. The median age sits above 49 years, and Japan is home to more than 80,000 centenarians, the largest number of people aged 100 or over anywhere in the world.
This aging profile reshapes everyday life and economics. There are fewer working-age adults to support a growing number of retirees, placing strain on pensions, healthcare, and the labor market. A frequently cited illustration is that Japan now sells more adult diapers than baby diapers — a stark signal of where the demographic balance has shifted. To ease labor shortages, Japan has cautiously expanded immigration, with around 3 million foreign residents as of 2024, a record high though still small relative to the total population.
Where Japanese People Live
Population in Japan is highly concentrated in a handful of metropolitan areas. The Greater Tokyo Area is the largest metropolitan region on the planet, with roughly 37 million residents — nearly a third of the entire country and a population larger than all of Canada. Tokyo serves as the political, financial, and cultural heart of the nation.
The second major cluster is the Kansai region around Osaka, whose metropolitan area holds about 19 million people and anchors much of western Japan's commerce and industry. Yokohama, just south of Tokyo and part of its greater urban sprawl, is the largest single city by population within its own limits, with around 3.7 million residents. Beyond these hubs lie Nagoya, Sapporo, Fukuoka, and Kobe, each a regional center, while rural prefectures continue to lose residents year after year.
Society and Demographics
Japan is one of the world's most ethnically homogeneous countries, with ethnic Japanese making up over 98% of the population. Japanese is the sole national language, and the dominant religious traditions are Shinto and Buddhism, often practiced together rather than as exclusive faiths. The country is governed as a parliamentary constitutional monarchy with Tokyo as its capital. For a fuller picture of the nation's geography, economy, and culture, see our japan country guide.
Frequently Asked Questions
What is the population of Japan in 2025?
Japan's population is approximately 123 million people in 2025, ranking it as the 12th most populous country in the world. The figure has been gradually declining since the national peak in 2008.
Why is Japan's population shrinking?
Japan's population is falling because of a very low birth rate of about 1.2 children per woman, combined with high life expectancy. Far more people die each year than are born, leading to a net loss of around 600,000 people annually.
What is the largest city in Japan by population?
Tokyo is the largest city, and its greater metropolitan area of roughly 37 million people is the most populous urban region in the world — home to nearly one in three Japanese residents.
How old is Japan's population?
Japan has the oldest population of any major country, with about 29% of people aged 65 or older and a median age above 49. It also has more centenarians than any other nation.