Polygon Area Calculator
Measure the area and perimeter of a field, garden, plot or any shape from its corner coordinates or a GeoJSON polygon, in hectares, acres, square metres and more.
About this tool
List the corners in order as you walk round the edge, clockwise or anticlockwise, one per line in any coordinate format. You can get them from your phone, a GPS unit or a mapping app by dropping pins at each corner. There’s no need to repeat the first point at the end. You can also paste a GeoJSON Polygon or Feature exported from mapping software. The drawing numbers each corner so you can spot one that’s out of order, and the tool warns if edges cross.
The area is calculated on the WGS84 ellipsoid with Karney’s method, as used by professional GIS software, so it’s accurate for anything from a garden to a county. It assumes straight edges between corners, so add more points along curved boundaries such as rivers and hedges. An acre is 4,047 m² and a hectare 10,000 m² (about 2.47 acres); a full-size football pitch is about 0.7 ha. For legal boundaries, rely on HM Land Registry plans or a surveyor. Your points are remembered on this device.