InspectMeshSTL measurement and scaling
Measure the model's axis-aligned bounds, choose the unit intended for its coordinates and calculate a proportional scale. Use a known source dimension to establish units before deciding whether the part is the right size.
Upload an STL to measure its width, height and depth.
Select a non-empty .stl file, up to 25 MiB.
Pressing Measure STL dimensions uploads the selected file for server processing. For inspection without upload, use the local STL Viewer. Read the processing and privacy policy.
STL geometry is stored as unitless coordinates, so STL files do not reliably contain unit metadata. You choose how those coordinates should be interpreted after measurement.
Open in STL Viewer to inspect the shape, local dimensions and point-to-point feature measurements in your browser.
Designing holes, pins or mating parts? Use the 3D Print Tolerance & Clearance Calculator before exporting the final STL.
| Result | Next action |
|---|---|
| The known reference dimension agrees | Check the intended orientation and nominal usable envelope, then verify the sliced placement. |
| All dimensions differ by one plausible unit factor | Establish a known dimension and source unit before choosing a correction. |
| One functional feature differs while overall size agrees | Inspect that feature or source CAD; do not globally resize |
| A nominal printer comparison is close | Check actual supports, brim and bed exclusions in the slicer |
| Value | Meaning |
|---|---|
| Coordinate span | Maximum minus minimum on a measured axis; it has no inherent physical unit in STL. |
| Interpreted size | The span expressed under the unit assumption supported by your source dimension. |
| Proposed proportional scale | Target span divided by current span; other axes change by the same factor. |
| Nominal printer comparison | A comparison within the implemented orientation and bed assumptions; the final sliced placement still needs review. |
Coordinate spans have no inherent physical unit in STL. Interpreted size follows your chosen assumption. A nominal printer comparison tests only the implemented orientation and bed assumptions, not a physical fit tolerance.
Resize and reopen a separate copy or choose the appropriate measurement method.
Check brims, excluded areas and placement after nominal fit
A 2-unit CAD width intended as inches is 50.8 mm, not 2 mm. Confirm a known reference dimension before applying a 25.4 correction. The batch cube similarly changes from 20 mm to 508 mm under an inch interpretation, without changing its source coordinates.
An illustrative 250 × 210 × 180 mm box cannot fit a nominal 180 mm cube bed in any right-angle orientation. It fits a nominal 256 mm cube geometrically, but its 6 mm margin on one axis does not reserve space for brims or excluded regions. Check the real slicer bed before printing.
Compare the same model against named printers