How Big Was the British Empire at Its Peak?

In 1920 and 1921 the British Empire covered about 33.6 million km², measured from its outline in TrueSize. Published estimates put it at about 35.5 million km², almost a quarter of the world's land. That is more than the whole of Africa (about 30.3 million km²) and about four times the 48 contiguous US states. In 1913 about 412 million people, almost a quarter of humanity, lived under British rule.

The British Empire in 1920, the year it reached its largest extent in the TrueSize timeline.

Open this map in TrueSize

The numbers

Region	Area	Source
British Empire, 1920	33.6 million km²	measured in TrueSize
British Empire, 1920	about 35.5 million km²	published estimate
Africa	about 30.3 million km²	common total
Mongol Empire, 1279	27.09 million km²	measured in TrueSize
Soviet Union	22.02 million km²	measured in TrueSize
Russia today	about 17.1 million km²	official total
Contiguous 48 US states	about 8.1 million km²	official total

Historians count colonies, protectorates and mandates differently, so published totals vary by a few million km². The TrueSize figure uses one outline for each year, the same method as for every other empire on the site.

Year by year in the timeline

The United Kingdom's entry in the TrueSize timeline carries the whole empire, so you can watch it grow and shrink.

Year	Area in TrueSize	What changed on the map
1858	15.7 million km²	the British Crown takes over the rule of India
1899	29.1 million km²	Sudan comes under joint British and Egyptian rule
1914	32.5 million km²	the First World War begins
1920	33.6 million km²	the peak, with former German colonies under British rule
1922	32.6 million km²	the Irish Free State and Egypt leave
1931	24.2 million km²	Canada leaves the outline under the Statute of Westminster
1934	22.6 million km²	South Africa leaves
1939	15.4 million km²	Australia leaves
1947	11.7 million km²	India and Pakistan become independent, and New Zealand leaves
1960	4.8 million km²	Nigeria and Cyprus become independent
1970	0.85 million km²	Fiji becomes independent; a few territories remain

The timeline counts a Dominion as its own state once it gained legislative independence, so Canada, South Africa, Australia and New Zealand leave the outline in steps. Other sources count the Dominions as part of the empire for longer.

Why it looks even bigger on most maps

The largest single piece of the empire, Canada, lies far to the north. The Mercator projection used by most web maps stretches land there about four times or more, so on a normal map the empire looks much larger than it was. India, Australia and the African colonies lie closer to the equator and are drawn closer to their real size.

The empire in 1950: after the independence of India and Pakistan, most of what remained was in Africa.

Open the 1950 map in TrueSize

Try it yourself

1. Click the Modern/Historical switch on the Home tab to open the timeline, then use Go to year to jump to 1920.
2. Search for the United Kingdom. In Historical mode, search shows what existed in that year, and the United Kingdom of 1920 comes with its whole empire.
3. Press the left and right arrow keys to jump to the previous or next change in its borders, or press play to watch the empire grow and shrink.

The timeline works on the web version and in the mobile app.

More comparisons

• The largest empires in history
• The Mongol Empire at true size
• How big was the Roman Empire?
• Historical Borders Map: See Any Country's Borders by Year

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