Topics
Sydney, 
Australia
4,150,917 people lived in Sydney in 2025. It is the 107th largest of the world's 12,138 cities, and the largest in Australia.
That figure counts the whole built-up area, not the area Sydney governs, so it may be far from the number the city publishes about itself. How the UN measures a city.
Verified 2026-09-30 · 73 canaries
People · every five years · 1975 to 2050
How Sydney grew
Where Sydney had 10 people in 1975, it had 18.7 in 2025.
On the UN's projection it will have 4.6 million people in 2050.
projected (after 2025) · how sure the UN is: high moderate low
How to read this: read it left to right, 1975 to 2050, one column every five years, the height being people. Hatching marks the projected years. Below, a strip of the UN's confidence: strong colour where the census maps are recent and detailed, pale where they are not, blank where the place was not counted as a city.
People · your family's years · 1975 to 2050
Sydney through your family’s years
Put in the years your family were born. You’ll see how many people lived in Sydney in each of those years, and when each of them turned 30.
Australia · every city · 2025
Where it is
How to read this: Sydney is the dot in colour with a ring around it. The grey dots are the other cities of Australia in 2025, 29 in all, 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, Sydney covered 1,317 km², and buildings, roads and other built-up land covered 312 km² of it. That is 75 m² of built-up land for each person, about a square 9 by 9 metres. Since 1975, its built-up land has grown by 49%, and its people have grown by 87%.
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 Australia
Its share of Australia
Of every 100 people in Australia in 2025, 15 lived in Sydney, which is 4.2 million people.
How to read this: 100 squares stand for everyone in Australia, one square for every 100th person. Count the coloured ones and you have Sydney's share; the grey remainder live somewhere else in the country.
Ranked by people · 2025
Cities of a similar size
In the world, 2025
- 103 Bamako Mali4,244,881
- 104 Luxor Egypt4,188,023
- 105 Belo Horizonte Brazil4,162,814
- 106 Wenzhou China4,158,195
- 107 Sydney4,150,917
- 108 Guadalajara Mexico4,135,440
- 109 Douala Cameroon4,104,516
- 110 Jaipur India4,071,754
- 111 Sana'a Yemen4,018,856
In Australia, 2025
- 107 Sydney4,150,917
- 127 Melbourne3,639,893
- 474 Perth1,079,374
- 476 Brisbane1,071,628
- 592 Adelaide879,249
- 1399 Point Cook404,501
- 1926 Gold Coast298,750
How to read this: names are in order of size, the leading number being each city's rank among all 12,138 in 2025; the bars share a scale within a list. A jump in the ranks means a city under 300,000 people, which is not given a page here.
Apparatus
Sources and method
The figures for Sydney 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 Sydney 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