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Karaj, 
Iran
3,598,661 people lived in Karaj in 2025. It is the 131st largest of the world's 12,138 cities, and the 3rd largest in Iran.
This is the UN's built-up area, drawn from satellite pictures and census maps rather than from the city limits, and the two can be a long way apart. The rule behind it.
Verified 2026-09-30 · 73 canaries
People · every five years · 1975 to 2050
How Karaj grew
Where Karaj had 10 people in 1975, it had 41.8 in 2025.
On the UN's projection it will have 4.1 million people in 2050. It passed a million people between 1975 and 1980.
projected (after 2025) · how sure the UN is: high moderate low
How to read this: each column is one of the UN's five-yearly estimates, 1975 through 2050, and taller means more people. Where a column is hatched the year has not happened yet. The strip under the columns is the UN's own confidence in each figure, palest where it is least sure; where it is blank the city was not on the list at all.
People · your family's years · 1975 to 2050
Karaj through your family’s years
Put in the years your family were born. You’ll see how many people lived in Karaj in each of those years, and when each of them turned 30.
Iran · every city · 2025
Where it is
How to read this: Karaj is the dot in colour with a ring around it. The grey dots are the other cities of Iran in 2025, 210 in all, led by Tehran, 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, Karaj covered 325 km², and buildings, roads and other built-up land covered 77 km² of it. That is 21 m² of built-up land for each person, about a square 5 by 5 metres. Since 1975, its built-up land has grown to 2.7 times its size, and its people are 4.2 times as many.
How to read this: each pale square is the city's whole area, the strong square inside it the part that is built on; one scale for all three, so a bigger square is more land. Hatched is the UN's projection.
Of every 100 people in Iran
Its share of Iran
Of every 100 people in Iran in 2025, 4 lived in Karaj, which is 3.6 million people.
How to read this: 100 squares, one for every 100th person in Iran; the coloured squares live in Karaj. The grey rest live in other cities, in towns or in the countryside.
Ranked by people · 2025
Cities of a similar size
In the world, 2025
- 127 Melbourne Australia3,639,893
- 128 Qingdao China3,616,657
- 129 Ankara Türkiye3,612,251
- 130 Kasaï-Oriental Democratic Republic of the Congo3,605,738
- 131 Karaj3,598,661
- 132 Berlin Germany3,560,908
- 133 Savar Bangladesh3,557,381
- 134 Peshawar Pakistan3,554,423
- 135 Lusaka Zambia3,510,723
In Iran, 2025
- 38 Tehran9,174,964
- 75 Mashhad5,398,248
- 131 Karaj3,598,661
- 272 Isfahan1,844,409
- 297 Ahwaz1,639,321
- 393 Tabriz1,309,004
- 491 Sarvestan1,039,168
- 523 Kharameh983,056
- 566 Shiraz914,496
How to read this: the figure in front of a name is where that city stands among the 12,138 cities the UN counted in 2025, and each bar is its people, on one scale per list. Numbers are missing where a city has fewer than 300,000 people and so has no page of its own.
Apparatus
Sources and method
The figures for Karaj 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 Karaj 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