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MapKmlTools

Measure KML Polygon Area & Perimeter

Calculate precise area and perimeter from KML, KMZ, or GeoJSON. Free browser-based GIS tool with no upload required for map analysis.

Frequently Asked Questions

Is KML Area Calculator free to use?

Yes, measuring area from GIS files is fully free.

Does KML Area Calculator upload my files to a server?

No, the area calculations are performed locally with no upload required.

What file formats does KML Area Calculator support?

Supports KML, KMZ, and GeoJSON files.

Which units does it support?

Supports Acres, Hectares, Square Miles, Square Kilometers, and Square Meters.

How accurate is the KML area calculation?

Very accurate. The tool uses geodesic calculations on the WGS84 ellipsoid (the same standard as professional GIS software like ArcGIS and QGIS), accounting for the Earth's curvature. For most land areas, results match surveying software to within 0.1%.

What units can I get the area in?

Results are shown simultaneously in Acres, Hectares, Square Kilometres, Square Miles, and Square Meters. You can switch between units using the dropdown without recalculating.

Why is my area result showing zero?

This happens when your KML contains only Points or open LineStrings (paths), not closed Polygons. Area can only be calculated for closed shapes. Lines will show a Perimeter/Length value instead.

Is my data uploaded to your servers?

No. All processing happens entirely in your browser. Your KML/KMZ files are never sent to any server — calculations are done locally using JavaScript.

What file size limits apply?

Files up to 50MB are supported. For files containing hundreds of polygons, the tool processes them all in a single upload and shows results in a sortable table you can export to CSV.

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What is Area Calculator?

The KML Area Calculator is a specialized GIS utility designed to measure the size of geographic shapes contained within KML (Keyhole Markup Language) files. Unlike simple map rulers, this tool processes complex files containing hundreds of polygons at once.

It uses geodesic calculations (WGS84 ellipsoid) to ensure accuracy over large distances, accounting for the curvature of the Earth. This makes it suitable for real estate, agriculture, and environmental planning.

When Should You Use This Tool?

  • •You have a KML file from Google Earth and need to know the total acreage.
  • •You need to find the center point (centroid) of multiple land parcels.
  • •You want to convert polygon measurements into a spreadsheet (CSV) for a report.
  • •You need to verify land survey data quickly without installing QGIS or ArcGIS.

How to Use Area Calculator

  1. Upload your KML/KMZ or GeoJSON file.
  2. The tool automatically analyzes the geometry.
  3. View results in the table below the map.
  4. Switch units (e.g., Acres to Hectares) using the dropdown.
  5. Download the report as CSV or copy to clipboard.

Real-World Use Cases

🚜

Agriculture & Farming

Farmers use this to measure field sizes in hectares or acres to calculate seed and fertilizer requirements accurately.

🏡

Real Estate & Land Development

Developers use it to aggregate the total area of multiple parcels and quickly feasibility studies.

🚒

Environmental & Emergency Services

Planners use it to measure affected areas (e.g., flood zones or fire perimeters) to estimate impact.

Supported Formats & Limits

  • Input Formats: .kml, .kmz, .json, .geojson
  • Max File Size: 50MB (Soft limit for browser performance)
  • Geometry Types: Polygons and MultiPolygons (for Area), LineStrings (for Length). Points are ignored for area.
  • Privacy: All processing is done client-side in your browser using JavaScript. No files are uploaded to our servers.