Actual Scale

See how big any city would be if it held the same number of people somewhere else on the map.

What it does

Search for any city (with over 1000 inhabitants), town, urban area, state, county or country and its outline is drawn on the map. Drag the shape anywhere in the world. As it moves, it grows or shrinks so that the area it covers always holds the same number of people as the place itself: small over a dense city, huge over empty land.

A Manhattan-sized outline dropped on rural Iowa balloons across the state. Dropped on Lagos or Dhaka it collapses. It turns population density from a number into something you can see and feel, and it makes city size comparisons honest: not "which city covers more land" but "how much land would it take to hold this many people here".

Things to try

• Drop Tokyo on the United States and see how far it spreads at American densities.
• Compare New York City with Los Angeles, Houston or Phoenix by dragging one over the other.
• Move a whole country, such as the Netherlands or Bangladesh, across Canada or Australia.
• Turn on the population heatmap to see why the outline changes size as it crosses cities, suburbs and countryside.
• Watch the panel at the bottom as you drag: it shows the place's actual area next to the ground its outline covers now.

Reading the heatmap

The heatmap colors the map by how many people live there: blue where there are a few, then cyan, yellow and orange, up to red in a city core. The legend counts the people in one square of the grid being drawn. Zoom out and the squares get bigger, so the numbers grow with them.

Chicago's densest neighborhoods are as red as the map gets. Any place with a higher density is shown in magenta.

How it works

The map sums a global population grid under the outline while you drag, entirely in your browser, and rescales the shape until the count under it matches the population of the place at home. Nothing is precomputed per city, so any place and any location on Earth work.

The data

• Population: the Global Human Settlement Layer population grid GHS-POP for 2025, 100 m resolution, by the European Commission Joint Research Centre (CC BY 4.0).
• Places and boundaries: cities, towns, administrative areas and countries from OpenStreetMap contributors (ODbL).
• Urban areas: the US Census Bureau 2020 urban areas and the GHS Urban Centre Database.
• Basemap: OpenFreeMap with OpenMapTiles.

Populations are model estimates from satellite and census data, so counts for a single small place can differ from official figures. The comparisons hold up well; the last digits do not.

Tips

• Right-click an outline (long-press on a phone) to remove it.
• Press m (or the gear) to open the settings: light or dark theme, miles or kilometers, whether a place comes with its far-flung islands and territories, the heatmap options, and this page.
• Share gives you a link that reopens the map with your outlines where you left them.

Open the map

Why I made it

I was inspired by The True Size Of..., which beautifully turns an abstract idea into something you can see: drag a country around and watch how the Mercator projection distorts its size. I wanted to do the same for population density: to make it something you can see and play with, not just a number in a table.

I also love programming and algorithms, and this project was full of unusual problems to solve: counting the people under an outline fast enough to keep up with a drag, resizing the shape on the fly until the count matches, and streaming a 100-meter population map of the whole planet to a browser in pieces small enough to load.

Made by Kyle Eckrich

For teachers

If you teach geography, social studies, math or anything else where population and density come up, you are welcome to use Actual Scale in your classroom and share it with your students. It is free, needs no account or sign-up, and a Share link opens the exact map you set up, so you can prepare a comparison before class. I would love to hear how you use it.

Contact

Questions, bugs, or ideas: [email protected]

Privacy

Actual Scale does not collect, sell, or share any personal information.