South Korea has a population of approximately 52 million people in 2025, making it the 28th most populous country in the world. Officially the Republic of Korea, the nation occupies the southern half of the Korean Peninsula in East Asia, yet it packs those tens of millions of residents into a land area of just over 100,000 square kilometres — producing one of the highest population densities of any large country on Earth.
How many people live in South Korea?
The current figure of roughly 52 million places South Korea between Colombia and Kenya in the global rankings, comfortably inside the world's 30 most populous states. To put that into perspective, it has a slightly larger population than Spain or Argentina, despite being far smaller in territory. With around 519 people per square kilometre, South Korea is denser than India and more than ten times denser than the world average. This intense concentration is shaped by geography: much of the country is mountainous, so the population clusters tightly in the lowland valleys and coastal plains where cities and farmland can exist.
A population that has begun to shrink
For most of the 20th century South Korea grew rapidly, but that era has ended. The population peaked around 2020 and is now declining at roughly -0.07% per year — a small figure today, but one expected to accelerate sharply in the coming decades. The driver is the country's extraordinarily low fertility rate, which fell to about 0.72 births per woman in 2024, the lowest ever recorded in any nation. A rate of about 2.1 is needed simply to keep a population stable, so South Korea is reproducing at roughly a third of replacement level.
The consequences compound quickly. If the trend holds, each generation would be only about one-third the size of the one before it. Demographers project that South Korea's population could fall to around 24 million by the year 2100 — less than half its current size. The government has spent more than $270 billion on incentives since 2006, from cash payments to childcare subsidies, yet births have continued to drop, making this one of the most closely watched demographic stories in the world.
Where South Koreans live
South Korea is overwhelmingly urban, and its population is concentrated to a remarkable degree around the capital. The three largest cities are Seoul, Busan and Incheon:
- Seoul — the capital, home to about 9.5 million residents and one of the world's most technologically advanced cities.
- Busan — about 3.4 million people, the second-largest city and the nation's principal port on the southeastern coast.
- Incheon — about 3 million residents, the site of the country's main international airport and gateway to the capital region.
The most striking statistic is the Seoul Capital Area, which combines Seoul, Incheon and surrounding Gyeonggi Province. This single metropolitan region holds roughly 26 million people — about half of the entire national population living in one corner of the country. Some districts within it exceed 17,000 people per square kilometre, ranking among the most densely settled places anywhere on the planet.
Who South Koreans are
South Korea is one of the most ethnically homogeneous societies in the world, with ethnic Koreans making up over 96% of the population. Korean is the sole official language, written in the distinctive hangul alphabet. In terms of religion, surveys suggest about 27% identify as Protestant Christian, 16% as Buddhist and 8% as Catholic, while close to 46% report no religious affiliation — making the religiously unaffiliated the single largest group.
The society is also aging fast. The median age is roughly 44 years, among the highest in Asia, and the share of citizens over 65 is climbing rapidly while the number of children falls. This combination of long life expectancy and very low fertility is what makes the country's demographic outlook so challenging for its workforce, pension system and economy. For broader context on the nation's geography, economy and culture, see our south-korea country guide.
Key population facts
- Population (2025 est.): ~52 million
- World rank: 28th most populous
- Annual growth rate: -0.07% (declining)
- Population density: ~519 people per km²
- Fertility rate: ~0.72 births per woman (world's lowest)
- Capital and largest city: Seoul
Frequently Asked Questions
Is South Korea's population growing or shrinking?
It is shrinking. The population peaked around 2020 and is now in slow decline at about -0.07% per year, a rate expected to speed up because of the world's lowest birth rate.
What is South Korea's fertility rate?
Around 0.72 births per woman as of 2024 — the lowest ever recorded for any country and far below the 2.1 needed to maintain a stable population without immigration.
What is the largest city in South Korea?
Seoul, the capital, with about 9.5 million people in the city itself and roughly 26 million in the wider Seoul Capital Area — about half the entire nation.
How does South Korea's population compare to North Korea's?
South Korea's roughly 52 million is about twice the population of North Korea, which has an estimated 26 million people on the northern half of the same peninsula.