Area Calculator
Click the map to draw a polygon. Area and perimeter are calculated automatically.
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Click on the map to start drawing a polygon.
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Area
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Perimeter
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Vertices
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About This Tool
The Area Calculator computes the surface area of any polygon you draw on the map. It is useful for land measurement, site planning, agricultural assessment, and any task that requires knowing the real-world extent of a geographic region.
Input
Polygon vertices placed by sequential map clicks. A minimum of three points is required. The polygon closes automatically when you click the first vertex again, or via the Close button. Both convex and concave shapes are supported.
Output
The geodesic area of the closed polygon in four units: square metres (m²), square kilometres (km²), acres, and hectares. All values update dynamically as you add or move vertices.
Key Concepts
- Geodesic area
- Area computed on the curved surface of the Earth using the WGS84 ellipsoid model, not on a flat map projection. Planimetric (flat-map) area overestimates real surface area at mid-latitudes and beyond — the discrepancy exceeds 1% for polygons larger than roughly 10 km².
- Acre
- A traditional unit of land area equal to 4,046.86 m² (exactly 1/640 of a square mile). Still the primary land measurement unit in the United States and the United Kingdom.
- Hectare
- Equal to 10,000 m² (a 100 m × 100 m square). The standard unit for land area in most metric countries, used in agriculture, forestry, and urban planning.