Map Area & Perimeter Calculator
Draw a boundary on a map to measure area in acres, hectares or square feet and calculate its perimeter.
Results are provided as is, for general information. Check anything important before relying on it. See the Terms of Use.
About this tool
Draw a boundary on a map to estimate the area inside and the perimeter around it. Click corners in order, drag the markers, or enter one latitude-first coordinate pair per line. Results include acres, hectares, square feet, square meters and square kilometers; perimeter can use feet, meters, kilometers or miles. The boundary joins corners with short great-circle arcs on a sphere of radius 6,371,000 meters. The model excludes slope, elevation, buildings and legal property boundaries. Map images load from OpenStreetMap; calculations run locally.
When to use it
Questions
How do I measure area and perimeter on a map?
Pan and zoom to the location, then click each corner in boundary order. With three or more valid corners, the preview includes the closing edge. Choose Finish boundary or click the first marker to stop adding points. Drag a marker or edit its coordinate row to adjust it. Undo removes the most recent corner; Clear starts again.
Can I enter coordinates without using the mouse?
Yes. Enter one latitude, longitude pair per line in Boundary coordinates. Decimal degrees and DMS are accepted. Do not repeat the first corner at the end: the tool closes the boundary automatically. Changing a row updates the measurement and allows more corners.
Which area units can I use?
Acres, hectares, square feet, square meters and square kilometers. One international-foot acre is exactly 4,046.8564224 square meters or 43,560 square feet; one hectare is 10,000 square meters. Switching units preserves the corners. The default is acres with perimeter in feet.
Is this a property survey?
No. Results estimate a selected shape on a spherical Earth. They do not identify ownership or legal boundaries, account for slopes, or replace a professional survey. Map images and drawn corners can be inaccurate. More displayed digits do not improve those inputs.
Why is my boundary rejected?
Use 3 to 100 different corners forming one simple boundary. Edges must not cross or touch non-neighboring edges, and the corners must enclose an area. Vertices and their curved edges must stay between 85°S and 85°N, with a continuous longitude span below 180°. Concave shapes and short date-line crossings are supported. Holes and multiple separate shapes are not supported.
How is a perimeter different from an area?
Area measures the surface inside the boundary; perimeter adds the lengths of every boundary edge, including the last-to-first edge. For the example's four corners near 40.712°N, 74.007°W, the model gives about 9,372.05 square meters inside and 390.960 meters around the boundary.
What does a shared boundary link reveal?
Copy map link includes every corner and the selected units in the fragment after #. Anyone receiving it can read the coordinates. The fragment is not sent in the initial page request; loading map images still reveals the viewed map areas and your IP address to OpenStreetMap.