GeoJSON Bounding Box

updated 9 May 2026

Before you start

Drop a .geojson file or paste the raw text. The tool computes the axis-aligned bounding box across every coordinate in every geometry — Point, LineString, Polygon, and the Multi* variants, plus nested GeometryCollections. The Copy button gives you a four-element array; the Download with bbox button hands back the original document with a top-level "bbox" member added (or replaced) per the RFC 7946 spec.

Coordinates are read as decimal degrees (WGS84). The math works for any projected coordinate system too — units just won't be lng/lat anymore — but the antimeridian-crossing optimisation in §5.2 of the spec is intentionally not applied here. If your features cross the 180° meridian, the bbox will span the whole world the long way around. That's the conservative behaviour and matches what most GIS libraries do.

How to use it

1. Paste your GeoJSON or drop a .geojson file into the left pane.
2. Click Compute bbox. The right pane shows the four-number array.
3. Click Copy bbox array for just the [minLng, minLat, maxLng, maxLat], or Download with bbox to save the original document with the bbox member added.

Example

Input:

{
  "type": "FeatureCollection",
  "features": [
    { "type": "Feature", "geometry": { "type": "Point", "coordinates": [-122.42, 37.77] }, "properties": {} },
    { "type": "Feature", "geometry": { "type": "Point", "coordinates": [-73.98, 40.75] }, "properties": {} }
  ]
}

Output bbox:

[-122.42, 37.77, -73.98, 40.75]

Tips & common pitfalls

• Order matters. RFC 7946 §5 specifies [west, south, east, north], i.e. [minLng, minLat, maxLng, maxLat]. Some tools emit [lat, lng] order — this one does not.
• Antimeridian crossings. A FeatureCollection that straddles 180°/−180° will produce a bbox that "wraps the long way" rather than two split boxes. If you need the spec-compliant crossing form, post-process the array yourself.
• Empty input. A document with no geometries (e.g. an empty FeatureCollection) returns no bbox — there's nothing to bound.
• Z values are ignored. If your coordinates have a third altitude/elevation entry, the bbox stays 2D. The spec does allow a 6-element 3D bbox, but that's rare in practice and not emitted here.

Related tools

• GeoJSON ViewerSee your data on a map and visually confirm the extent.
• GeoJSON ValidatorMake sure the file is RFC 7946-compliant before computing bounds.
• Simplify GeoJSONReduce vertex count while keeping the same bounding extent.
• GeoJSON FormatterPretty-print or minify your file once the bbox is added.

Frequently asked questions