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Japan vs UK Size: How Much Bigger Is Japan?

By SimpleMapLab·Published 15 May 2026·Reviewed against CIA Factbook 2024·CC-BY 4.0

Two iconic island nations. Japan covers 145,937 sq mi (377,975 km²); the UK covers 94,058 sq mi (243,610 km²). Japan is 1.55× larger — about half as big again as the UK. Japan also has 1.81× the population, a 17% larger economy ($4.21T vs $3.59T), and 2.39× more coastline. Both rank as G7 economies and former colonial empires.

Diagram showing the UK overlaid inside Japan at true equal-area scale. Japan 145,937 sq mi; UK 94,058 sq mi; ratio 1.55×.Japan is 1.55× the size of the UKJapan 145,937 sq mi · UK 94,058 sq mi · Two island nations comparedJAPANUKsimplemaplab.com/size-comparisons/japan-vs-uk · CC-BY 4.0
UK overlaid inside Japan at true equal-area scale. The UK covers ~64% of Japan's footprint; the leftover (~52K sq mi) is the size of New York State.
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At a glance: Japan vs UK by the numbers

MetricJapanUKRatio
Total area (sq mi)145,93794,0581.55× JP
Population (2024)124,500,00068,700,0001.81× JP
Density (/sq mi)8537361.16× JP
GDP (2024)$4.2T$3.6T1.17× JP
Coastline (mi)18,4877,7232.39× JP
Islands6,8526,289—
Highest point (ft)12,388 (Fuji)4,413 (Ben Nevis)2.81× JP
World rank62nd (area), 4th (GDP)80th (area), 6th (GDP)—

The archipelago twins: Japan and the UK

Japan and the UK are the world's two largest island-nation economies. Both are archipelagos: Japan has 6,852 islands (4 large: Honshu, Hokkaido, Kyushu, Shikoku); the UK has 6,289 islands (dominated by Great Britain and Northern Ireland). Both are surrounded by water — Japan by the Pacific and Sea of Japan; the UK by the Atlantic, North Sea, and Irish Sea.

Both have outsized cultural and economic influence relative to their geographic size. Japan ranks #4 globally by GDP ($4.21T); the UK ranks #6 ($3.59T). Together they account for roughly 7% of world GDP on less than 0.5% of world land area. Both maintained constitutional monarchies through the 20th century. Both had global empires that collapsed after WWII — the British Empire at 146× today's UK, the Japanese Empire at ~20× today's Japan.

Drawn to scale: Japan next to the UK

Both island nations at the same area-per-pixel scale.

Side-by-side equal-area: Japan next to UK at the same pixel scale.Japan is 1.55× the area of the UKJapan145,937 sq miUnited Kingdom94,058 sq mi
Japan rendered with rotate −137°, parallels 33/41°N; UK with parallels 50/58°N. Both equal-area-preserving.

What else is the size of Japan?

What else is the size of the UK?

10 surprising facts about Japan vs the UK

  1. Japan is 1.55× the UK. 145,937 vs 94,058 sq mi.
  2. Japan has 1.81× the UK's population. 124.5M vs 68.7M.
  3. Japan's economy is 17% bigger. $4.21T (#4 world) vs $3.59T (#6).
  4. Japan has 2.39× more coastline. 18,487 vs 7,723 mi — Japan's coastline is the world's 6th-longest.
  5. Both are archipelagos with similar island counts. Japan 6,852, UK 6,289 — UK has fewer but more compact distribution.
  6. Mt. Fuji is 2.81× Ben Nevis. 12,388 ft vs 4,413 ft. Japan has 21 peaks over 10,000 ft; the UK has none.
  7. Japan is the only G7 country in Asia. Joined in 1973 (the original G6 + Canada). Geographically the most distant G7 member.
  8. Japan's empire (1942 peak) was 20× today's Japan. ~2.9M sq mi. The British Empire at 1920 was 146× today's UK.
  9. Both have constitutional monarchies. Emperor Naruhito (Japan, since 2019) and King Charles III (UK, since 2022). Japan's imperial line is the world's oldest continuous monarchy by tradition.
  10. Both drive on the left. Japan and the UK are 2 of the ~35 countries worldwide that drive on the left side of the road.

Methodology and sources

Area: CIA World Factbook 2024.

GDP: IMF World Economic Outlook (October 2024), nominal USD.

Projections: Japan with d3.geoConicEqualArea (rotate −137°, parallels 33/41°N); UK with parallels 50/58°N. Both equal-area-preserving. Last reviewed 15 May 2026.

Frequently asked questions

Yes. Japan covers approximately 145,937 sq mi (377,975 km²); the UK covers 94,058 sq mi (243,610 km²). Japan is 1.55 times larger by total area — a difference of about 52,000 sq mi (roughly the size of New York State).
Japan is 1.55× larger by total area. In absolute terms, Japan exceeds the UK by 51,879 sq mi — about the size of Greece, Iceland, or the state of Alabama.
Japan: ~124.5 million people. UK: ~68.7 million. Japan has 1.81× the UK's population. Density: Japan 853/sq mi vs UK 736/sq mi — Japan is 16% denser. Both are among the world's most densely populated industrialised nations.
Japan has the larger economy: $4.21 trillion GDP (2024) vs the UK's $3.59 trillion — Japan is 1.17× the UK economically. Japan ranks #4 globally by GDP (after USA, China, Germany); UK ranks #6. Together they total $7.8 trillion — roughly 7% of world GDP.
Japan: 6,852 islands across its archipelago, of which 4 are large (Honshu, Hokkaido, Kyushu, Shikoku) and ~430 are inhabited. UK: 6,289 islands across the British Isles, dominated by Great Britain and Northern Ireland, with about 132 inhabited. Both are quintessential archipelago nations.
Japan has dramatically more: 18,487 mi vs the UK's 7,723 mi — Japan has 2.39× more coast. Japan's coastline is the world's 6th-longest (after Canada, Norway, Indonesia, Russia, Philippines). The UK's is 12th-longest. Both massively outpunch their area class — being archipelagos means coast in every direction.
Yes — both had significant 19th–20th century empires. The Japanese Empire (1868–1945) at its 1942 peak covered about 2.9 million sq mi (Korea, Manchuria, Taiwan, Southeast Asia, Pacific islands) — about 20× today's Japan. The British Empire (peak 1920) covered 13.7 million sq mi — about 146× today's UK. Both empires effectively ended after WWII.
Japan's Mt. Fuji (12,388 ft) is 2.81× the height of the UK's Ben Nevis (4,413 ft). Japan has 21 peaks over 10,000 ft; the UK has none. Japan's tectonic activity (Pacific Ring of Fire) creates dramatic relief; the UK is geologically older and weathered down to low rounded ranges.
Japan (145,937 sq mi) is approximately Germany × 1.06, Vietnam × 1.14, Norway × 0.98, or California × 0.89. Among countries, Japan ranks 62nd by area — smaller than expected given its economic and cultural influence.
The UK (94,058 sq mi) is approximately Oregon × 0.98, Romania × 1.02, Ghana × 1.02, or Guinea × 0.99. The UK ranks 80th globally by area.

Related size comparisons

Suggested citation: SimpleMapLab (2026). Japan vs UK Size. Retrieved from https://www.simplemaplab.com/size-comparisons/japan-vs-uk. CC-BY 4.0.