Free tool
Draw a box, read the three open building datasets for it, and download the polygons as GeoJSON for QGIS or ArcGIS. No account, no email. The licence and the attribution travel inside the file.
Drag the box to move it. Drag a corner to resize it.
Nothing to download yet. Draw a box first.
Every picture below is one answer from this tool, drawn straight from the file it hands you. Nothing is redrawn and nothing is tidied up.
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All three allow commercial use, and all three ask something back. OpenStreetMap and Google under ODbL want your derived database shared on the same terms. Google under CC BY 4.0 and Microsoft under CDLA Permissive 2.0 only want credit. They also disagree about the same ground, and the disagreement is the useful part.
| Dataset | Coverage | Vintage | Licence | What the polygons look like |
|---|---|---|---|---|
| OpenStreetMap | Global, and as complete as the local mapping community has made it. Dense in most European and North American cities, thin in places nobody has mapped yet. | Live. Whatever the map says right now. | ODbL 1.0 | Drawn by people. A terraced row is often one polygon. Rich attributes: address, levels, name, roof shape. |
| Microsoft Global ML Building Footprints | Global. A model ran over satellite and aerial imagery, so it fires on buildings a surveyor never visited and misses nothing on purpose. It also stops at whatever the imagery showed. | Release of 3 February 2026 | CDLA Permissive 2.0 | Detected by a model. One polygon per building, with a confidence score and a height estimate where the imagery allowed one. |
| Google Open Buildings v3 | Africa, South Asia, South East Asia, Latin America and the Caribbean only. Not Europe, not North America, not Australia. Inside that footprint it is the densest of the three. | Imagery to May 2023 | CC BY 4.0 or ODbL 1.0 | Detected by a model. Splits a compound into many small polygons, with a confidence score and an area in square metres. |
Measured on 2026-08-14 for the box 2.345400,48.852100,2.359000,48.861100, around the Île de la Cité. The numbers below are what this tool returned, not an estimate. Île de la Cité and the Latin Quarter, Paris, 1.0 km².
| Dataset | Buildings | Total footprint | What happened |
|---|---|---|---|
| OpenStreetMap | 1,391 | 454,132 m² | Answered live from Overpass in about six seconds. 326 m² per polygon. |
| Microsoft Global ML Building Footprints | 213 | 568,930 m² | One 91 MB file, quadkey 120220011, read whole and filtered to the box. 2,671 m² per polygon. |
| Google Open Buildings v3 | 0 | 0 m² | No coverage. Google Open Buildings v3 does not publish Europe. |
Read those two rows again. OpenStreetMap returns 6.5 times more polygons than Microsoft, and Microsoft covers 25% more ground. Both are true. In central Paris the model merges a whole block into one shape, 2 671 m² on average, while people drew each building, 326 m² on average. So a count tells you how the data was cut, not how much of the city is in it. That is why this page never ranks a source by its count, and why it shows total footprint area beside every one.
The box goes to Overpass, the OpenStreetMap query service, and comes back with every way and multipolygon relation tagged as a building. There is no vintage: you get the map as it stands at the moment you press the button. Relations are stitched back into proper polygons, so a building with a courtyard keeps its hole instead of arriving as loose lines.
Microsoft publishes the world as 30,344 gzipped files, one per Web Mercator zoom-9 tile, 117 GB in total. There is no index inside a file, so the only way to get a small box is to read the whole tile and throw the rest away. The median tile is small enough to do that inside a web request. A dense city is not: central Paris is a single 91 MB file. When the tile is too big, this page names the exact file instead of spinning.
Google Open Buildings v3 is 1.85 billion buildings in 312 files, 178 GB in total, split by S2 cell. The median file is 164 MB and the largest is 8.4 GB. Almost no box can be sliced out of that inside a web request, so for Google this page is mostly a locator: it tells you which of the 312 files covers your area and how big it is. That is still the answer most people are looking for.
Google publishes the boundary of every cell it released, and this page carries a copy. So when the answer is "Google has nothing here", that comes from Google's own index, not from a lookup table someone typed. Google does not cover Europe, North America or Australia.
Every file this page writes carries its licence and its attribution string inside the GeoJSON, so the obligation survives the file being renamed or passed on. Read the licence before you publish anything derived from ODbL data: it is share-alike, and the other two are not.
ODbL 1.0
Keep this line with the data
© OpenStreetMap contributors, ODbL 1.0
Read the licenceCDLA Permissive 2.0
Keep this line with the data
Microsoft Global ML Building Footprints, CDLA Permissive 2.0
Read the licenceCC BY 4.0 or ODbL 1.0
Keep this line with the data
© Google Open Buildings v3, CC BY 4.0 or ODbL 1.0
Read the licenceOpen building data has two failure modes, and this page shows you both. OpenStreetMap is thin where nobody has mapped. Microsoft and Google are frozen at the date of their imagery, so anything built since is missing. If the box you just drew came back short, the buildings are still in the imagery. Detecting them is what our QGIS plugin does.
Longer read on the three ways to get building polygons, and the filtering step that decides whether the layer is usable: How to detect building footprints in QGIS
