What is Area Calculator Map?

Draw polygons on a map to measure enclosed areas. Works for land plots, property boundaries, parks, or any region you need sized up, with results in multiple units.

The map uses OpenStreetMap or Esri satellite tiles and Turf.js to compute the area of any polygon you draw. Each click adds a vertex, clicking the first point closes the shape, and the result updates instantly in square meters, square kilometers, hectares, acres, square feet, or square miles. A Nominatim-powered search box locates addresses fast, and you can export the measurement as a PNG, a KML file for GIS apps, or a CSV of the vertex coordinates. Switch to circle mode to drop a point and drag out a radius for coverage zones and proximity rings, import an existing KML to re-measure a boundary you already have, and copy a share link that reopens the exact drawing for a colleague.

How to use

1. Click on the map to place polygon points around the area you want to measure.
2. Close the polygon by clicking the first point again. The area is calculated instantly in your chosen unit.
3. Switch between six area units (square meters, square kilometers, acres, hectares, square feet, square miles). Export the result as a PNG map image, a KML file for Google Earth and QGIS, or a CSV table of every vertex.

When to use

• Estimating the square footage of a vacant lot before listing it for sale.
• Measuring a farm field for crop planning when you don't have a survey on file.
• Sizing a roof from satellite view for a solar-panel quote without climbing up.

Result

A real estate agent draws a polygon around a vacant lot in their city, reads the area as 2,450 square meters (0.6 acres), and downloads the annotated map view for their property listing.

FAQ

How accurate is the area measurement compared to a professional survey?

For a polygon under 5 hectares with clean satellite imagery, expect roughly 1–3% deviation from a surveyed value. Tile alignment and your own click precision are the main sources of error, not the math itself. Use it for estimates, not legal boundaries.

Why are my acres and square meters slightly different from another tool's result?

Turf.js measures area on the Earth's curved surface using the spherical excess formula, so the result accounts for latitude. Tools that treat the polygon as flat give slightly different numbers, especially for large or high-latitude shapes.

Can I undo a misplaced point without restarting?

Yes. The undo button removes the last vertex you placed and lets you keep drawing. If you've already closed the polygon, undo first reopens the shape, then the next undo trims the latest point.

Does the tool work for irregular shapes with concave edges?

It does, as long as the boundary doesn't cross itself. Concave outlines, narrow inlets, and L-shapes are fine. If your polygon's edges intersect, Turf.js returns an invalid result, so re-draw with simpler vertices.

Can I export the measurement and the map view together?

Yes — and you can pick the format. PNG saves the visible map (street or satellite, matching whichever layer you have active) with the polygon and area annotation baked in, KML opens straight in Google Earth or QGIS, and CSV gives you every vertex's lat/lng plus the area and perimeter for spreadsheet work.

Related Tools