Bounding Box Calculator
Calculate the bounding box of a list of coordinates or a GeoJSON file. Get the bbox array, Leaflet bounds, WKT envelope and a downloadable polygon.
Bounding box formats
- GeoJSON bbox — [west, south, east, north]
- [-74.006, 40.7128, 2.3522, 51.5074]
- Leaflet bounds — [[south, west], [north, east]]
- [[40.7128, -74.006], [51.5074, 2.3522]]
- WKT polygon
- POLYGON ((-74.006 40.7128, 2.3522 40.7128, 2.3522 51.5074, -74.006 51.5074, -74.006 40.7128))
Box as GeoJSON
What is the Bounding Box Calculator?
Give this calculator a list of latitude/longitude points or a whole GeoJSON document and it returns the smallest box that contains them all: north, south, east and west edges, the centre point, and the box's ground width and height in kilometres.
- Bounding box from a coordinate list or any GeoJSON document
- Output as GeoJSON bbox, Leaflet bounds, WKT polygon and GeoJSON polygon
- Centre point plus the box's width and height in kilometres
- Correct handling of boxes that cross the antimeridian
- Catches swapped latitude/longitude values in GeoJSON input
- 100% client-side — coordinates never leave your browser
How to use the Bounding Box Calculator
- 1
Choose whether to enter a coordinate list or paste GeoJSON.
- 2
For a list, put one "latitude, longitude" pair on each line.
- 3
For GeoJSON, paste a Feature, FeatureCollection or bare geometry.
- 4
Copy the bbox array, Leaflet bounds or WKT, or download the box as GeoJSON.
About the Bounding Box Calculator
Give this calculator a list of latitude/longitude points or a whole GeoJSON document and it returns the smallest box that contains them all: north, south, east and west edges, the centre point, and the box's ground width and height in kilometres. GeoJSON mode scans every position in the file, including nested geometries and feature collections.
The result is offered in the formats you actually paste into code: the RFC 7946 bbox array [west, south, east, north], Leaflet's [[south, west], [north, east]] bounds, a WKT polygon, and a downloadable GeoJSON polygon of the box itself.
It also handles the antimeridian properly. Points spread across ±180° would produce a box spanning almost the whole planet if you just took the minimum and maximum longitude, so the calculator finds the widest empty gap instead and reports a correctly wrapped box — with a clear note when that happens. Everything is computed locally; nothing is uploaded.
Frequently asked questions
What is a bounding box?
It is the smallest axis-aligned rectangle that contains a set of geographic points, described by its minimum and maximum latitude and longitude. Maps use it to set the initial view, and spatial indexes use it as a fast first-pass filter before doing exact geometry maths.
What order do the numbers go in a GeoJSON bbox?
RFC 7946 specifies [west, south, east, north] — minimum longitude, minimum latitude, maximum longitude, maximum latitude. Leaflet, confusingly, wants [[south, west], [north, east]], so this tool prints both to save you the guesswork.
How do I find the bounding box of a GeoJSON file?
Paste the file into GeoJSON mode. Every position in the document is collected — including nested geometry collections and multi-geometries — and the minimum and maximum on each axis become the box.
What happens when the box crosses the antimeridian?
The west value ends up numerically greater than the east value, which RFC 7946 explicitly allows. This calculator finds the largest empty longitude gap so it can produce the genuinely smallest box, and it warns you when the result wraps, because some libraries need it split in two.
Why is my bounding box enormous?
Usually because one point has its latitude and longitude swapped, or a stray zero row is sitting in the data pulling the box out to 0,0 in the Gulf of Guinea. The point count and centre shown here make outliers easy to spot.
Is my data uploaded to calculate the box?
No. Parsing and the maths run entirely in your browser, so confidential point sets and unreleased GeoJSON stay on your device. The page keeps working offline too.
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