Convert GeoJSON to TopoJSON online for free — right in your browser. No upload, no sign-up, batch conversion, coordinate systems and attributes preserved.
Efficiently convert from GEOJSON to TOPOJSON format
All processing is done locally in your browser
Output standard TOPOJSON format
Convert geojson to topojson online for free — right in your browser. No upload, no sign-up, batch conversion, coordinate systems and attributes preserved.
GeoJSON is a geospatial data interchange format based on JSON. It can represent Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection geometries. Defined by RFC 7946, GeoJSON has become one of the most popular data exchange formats in web GIS. GeoJSON files use WGS84 coordinates and support Feature objects with associated properties and FeatureCollections for organizing multiple features.
TopoJSON is a GeoJSON extension developed by Mike Bostock that encodes topology to eliminate redundant shared boundaries. Unlike GeoJSON where each polygon independently stores all vertices, TopoJSON uses arcs to share common boundaries between adjacent features, reducing file sizes by over 80%. TopoJSON is particularly suited for rendering large numbers of adjacent areas such as administrative district maps.
GeoJSON stores every polygon independently, so adjacent regions repeat their shared border — twice the coordinates and visible seams in D3 visualizations. TopoJSON encodes the topology once: shared arcs are stored a single time, typically shrinking administrative-boundary files by 70–90%. That is why TopoJSON is the format behind fast-loading D3 choropleths and why it is the standard choice when publishing boundary data at scale.
Boundary datasets typically shrink 70–90% thanks to shared-arc encoding and quantization. Exact savings depend on how many shared borders exist.
TopoJSON quantizes coordinates, introducing sub-millimeter rounding at typical scales — invisible on maps, and adjustable in advanced options.
Yes — the TopoJSON to GeoJSON converter reconstructs the original geometry losslessly from the topology.
Upload your GeoJSON file — drag and drop it onto the page, or browse from your device. You can add several files at once for batch conversion.
The conversion runs automatically in your browser. No upload, no server — your data stays on your device the entire time.
Download the TopoJSON file. Each input produces its own output, ready to use in your GIS, web map, or archive.