Japan vs South Korea

Japan is 3.77 times larger than South Korea. South Korea would fit into Japan about 3.8 times.

JapanSouth KoreaJapan moved onto South Korea · Equal-area projection
3.77×
Japan is 3.77× the area of South Korea.
JapanSouth Korea
Area377,972 km²100,295 km²
Population123,366,73451,684,564
Density326 / km²515 / km²
CapitalTokyoSeoul
RegionEastern AsiaEastern Asia
CoastlineHas a coastHas a coast
Neighbours01

Why the map you grew up with disagrees

On a Mercator map, area grows with distance from the equator. Japan sits at about 37°N and is stretched to 1.59× its true area; South Korea at 36° N is stretched to 1.54×. Here the two are distorted about the same amount, so Mercator gets this pair roughly right. The figure above uses the Equal Earth projection, where every square kilometre is drawn the same size.

Questions about this pair

Is Japan bigger than South Korea?
Yes. Japan is 3.77 times larger than South Korea. Japan covers 377,972 km² and South Korea covers 100,295 km².
How many times does South Korea fit into Japan?
About 3.8 times: Japan has 3.77× the area of South Korea.
Why do Japan and South Korea look different on Google Maps?
Web maps use the Mercator projection, which stretches area with distance from the equator. Japan is drawn about 1.59× its true area there and South Korea about 1.54×. For this pair the distortion is similar, so Mercator gets the comparison roughly right. Kartavera uses Equal Earth, where every square kilometre is drawn the same size.
Which has more people, Japan or South Korea?
Japan: 123,366,734 people against 51,684,564. Density: Japan 326 per km², South Korea 515 per km².