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Belfast, 
United Kingdom
441,925 people lived in Belfast in 2025. It is the 1262nd largest of the world's 12,138 cities, and the 15th largest in the United Kingdom.
The UN measures every city in the world the same way, by where the buildings are rather than where the boundary runs, so this figure and Belfast's own can differ widely. What counts as a city here.
Verified 2026-09-30 · 73 canaries
People · every five years · 1975 to 2050
How Belfast grew
Where Belfast had 10 people in 1975, it had 14.7 in 2025.
On the UN's projection it will have 541,746 people in 2050.
projected (after 2025) · how sure the UN is: high moderate low
How to read this: one column every five years, 1975 to 2050; its height is the number of people. Hatched columns are the UN's projection. The thin strip beneath says how sure the UN is of each figure: the stronger the colour, the surer. A blank means the place was not on the UN's list of cities that year.
People · your family's years · 1975 to 2050
Belfast through your family’s years
Put in the years your family were born. You’ll see how many people lived in Belfast in each of those years, and when each of them turned 30.
United Kingdom · every city · 2025
Where it is
How to read this: Belfast is the dot in colour with a ring around it. The grey dots are the other cities of the United Kingdom in 2025, 150 in all, led by London, each drawn with an area that matches its people. Countries next door are outlines only.
Area and built-up land · km²
How much land it covers
In 2025, Belfast covered 141 km², and buildings, roads and other built-up land covered 30 km² of it. That is 67 m² of built-up land for each person, about a square 8 by 8 metres. Since 1975, its built-up land has grown by 49%, and its people have grown by 47%.
How to read this: the outer pale square stands for all the land the city covers, and the solid square inside it for the part with buildings, roads and the like on it. All three squares share a scale, so you can compare them by eye. A hatched one is a year the UN has projected.
Of every 100 people in the United Kingdom
Its share of the United Kingdom
Of every 1,000 people in the United Kingdom in 2025, 6 lived in Belfast, which is 441,925 people.
How to read this: 1,000 squares stand for everyone in the United Kingdom, one square for every 1,000th person. Count the coloured ones and you have Belfast's share; the grey remainder live somewhere else in the country.
Ranked by people · 2025
Cities of a similar size
In the world, 2025
- 1258 Nizamabad India442,690
- 1259 Santa Marta Colombia442,455
- 1260 Blitar Indonesia442,219
- 1261 Anantapur India442,201
- 1262 Belfast441,925
- 1263 Toyohashi Japan441,665
- 1264 Chief Albert Luthuli Park South Africa441,204
- 1265 Zhanjiang China440,587
- 1266 Manizales Colombia440,407
In the United Kingdom, 2025
- 1046 Leicester530,264
- 1058 Edinburgh521,784
- 1137 Portsmouth488,385
- 1188 Brighton467,937
- 1262 Belfast441,925
- 1308 Coventry427,678
- 1455 Cardiff390,692
- 1473 Bournemouth386,557
- 1637 Middlesbrough349,436
How to read this: the number before each name is its place among all 12,138 cities in the world in 2025; bars are people, on one scale per list. Only cities that reach 300,000 people have a page here, so a gap in the numbers is a smaller city.
Apparatus
Sources and method
The figures for Belfast are the UN's own, at five-year steps: an estimate for each of 1975 to 2025, then projection to 2050. Projected years are drawn hatched, and the UN publishes no range of uncertainty for a city. What a city means here, how the UN measures one, and why that number can differ from the one Belfast publishes about itself: how the figures here are put together.
Sources: UN WUP 2025 · Natural Earth · flag-icons. Every source, its licence and how to cite it →
Verified 2026-09-30 · 73 canaries