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Measure STL Online

Measure STL, OBJ and STEP meshes in your browser. Pick two surface points, review model dimensions and calculate approximate surface area in selected units.

Enable JavaScript to open a model and use the interactive workspace.

How do I use this tool?

  1. Choose an OBJ, STL or STEP model from your device.
  2. Preview your model and adjust the settings.
  3. Pick two surface points or calculate area.

What does this tool do?

Measurements use the displayed triangle mesh and selected output unit. Surface area is approximate. Signed volume is diagnostic only: nested or intersecting shells and reversed normals can affect the value.

What are the file limits?

Models are processed locally. Inputs are limited to 50 MB per file and 500,000 triangles after import. Individual operations may have lower limits described below. Performance depends on your device.

JavaScript, WebAssembly and WebGL are required for the interactive workspace.

How are models processed?

Mesh loading and rendering use Three.js. STEP import and tessellation use occt-import-js, based on Open Cascade. These sources describe the underlying libraries; this tool's supported features and limits are listed on this page.

Frequently asked questions

How do I measure a distance on an STL model?

Open the model and click two points on its visible triangle surface. The tool displays their straight-line distance in the selected output unit. A third click starts a new measurement; it does not measure a path along the surface.

Are STL measurements always in millimeters?

No. STL does not reliably identify the unit of its coordinates. Select the correct source unit and your preferred output unit before measuring. STEP input is read into millimeters using its embedded length units.

How accurate is the point-to-point measurement?

It depends on the source mesh, tessellation precision and the points you select. Measurements use the displayed triangles, not exact CAD curves or manufacturing tolerances. They do not automatically identify hole diameters or wall thickness.

Can I measure surface area and volume?

Yes, the available diagnostics calculate triangle surface area and conditionally show signed volume for closed, consistently wound meshes. Intersecting or nested shells can affect how volume should be interpreted.