How to use this tool
- Choose an STL file from your device; the model stays local.
- Select whether the source coordinates represent mm, cm or inches.
- Rotate and zoom the projection to inspect facets and model orientation.
- Check boundary/non-manifold edges before using a volume estimate.
Calculation method and formula
Surface area is the sum of triangle areas ½‖(b−a)×(c−a)‖. A closed, consistently oriented triangle mesh can estimate signed enclosed volume by tetrahedral summation.
WORKED EXAMPLE
A correctly oriented 10 × 10 × 10 mm cube built from 12 triangles has 600 mm² surface area and 1,000 mm³ volume.
What the calculation does not cover
- STL carries no inherent real-world unit metadata, material or design intent.
- A passing edge test does not detect all self-intersections or certify a solid.
- Open or inconsistently oriented meshes have their volume withheld; file size and facet limits apply.
Common questions
Does uploading STL send my design to a server?
No. The browser reads the selected file directly for the geometry viewer. No CAD model-upload API is involved.
Can this replace inspection-grade CAD software?
No. It provides mesh-based measurements and a browser preview, not a certified geometric inspection.
Engineering use: This calculator is a transparent estimate for its defined model; confirm units, applicability, standards and engineering decisions independently.