Measure STL, STEP & GLB files online — dimensions, volume & mass
Open a CAD or mesh file and measure distances, angles and hole diameters, read dimensions, volume, surface area and mass by material, cut cross-sections and export a parts BOM — all in your browser. Free, private, nothing uploaded.
Measure
Click a part to isolate it and see its own dimensions.
Dimensions & mass
Load a model to see its dimensions, volume, surface area and mass.
Cross-section
Measuring tips
- Snap is on by default — clicks land on the nearest corner or edge vertex, which is where CAD tessellations keep exact dimensions.
- Hole diameters: click three points spread around the rim (not in a line). The fit is a true 3D circle, so it works on tilted faces too.
- Units: STEP/IGES are read in millimetres from the file. Mesh formats carry no units, so the tool applies each format’s convention — if a model looks 10×, 25×, or 1000× off, switch File units rather than the display unit.
- Mass multiplies the closed-mesh volume by the material density — pick the right material, and expect open or hollow meshes to read low.
- X-ray + cross-section together show internal pockets, wall thickness and hidden holes.
Capabilities
What it does
- Opens STEP / IGES (via OpenCascade in WebAssembly) and every common mesh format — STL, 3MF, OBJ, GLB/glTF, FBX, PLY, USDZ — locally in your browser.
- Point-to-point distance with X/Y/Z deltas, three-point angles, and true 3D hole diameters from three rim points — clicks snap to corners and edges for exact numbers.
- Dimensions, volume, surface area, centre of mass and mass / print weight by material (PLA, resin, aluminium, steel, brass…) for the whole model or any single part.
- Live cross-section: cut along X, Y or Z, see the section outline and its area, and combine with X-ray shading to inspect walls and hidden pockets.
- STEP assemblies show a parts list — isolate a part, read its own numbers, export a BOM as CSV, or download one part as STL or GLB.
- 100% in your browser — proprietary CAD never leaves your device. No account, no upload, no watermark.
Process
How it works
- Drop a modelDrag a STEP, IGES, STL, 3MF, OBJ or GLB file onto the tool. It’s read locally — CAD files are tessellated by OpenCascade running in WebAssembly.
- Measure & inspectPick Distance, Angle or Hole ⌀ and click on the model; switch units between mm, cm and inch. Dimensions, volume and mass update for the selected part or the whole model.
- Section & exportCut a cross-section to check internal geometry, then save a screenshot with your dimensions, export the BOM as CSV, or download a part as STL/GLB.
Before you print
How to check STL dimensions before 3D printing
Drop the STL and read its bounding box (X × Y × Z) in mm or inches in the Dimensions & mass panel — that is the size it will print at. Use Distance to verify a critical feature (a clearance, a wall, a hole pitch), Hole ⌀ for fits, and compare the box against your printer bed. If the numbers are 25.4× off, the file was exported in inches: switch File units here or fix it permanently with the STL scale tool. For bed fit, filament grams and cost in one verdict, run the Printability checker.
CAD files
Open STEP files without CAD software — a viewer with no upload
STEP and STP files are tessellated by OpenCascade running in WebAssembly, so you get a real CAD viewer in the browser: rotate, zoom, pan, X-ray shading, the assembly tree with part names and colours, isolate any part and read its own dimensions, volume and mass. Nothing is uploaded — confidential customer CAD stays on your machine. Need a mesh for printing? Download a part as STL or GLB, or use the STEP to STL converter.
Notes
Good to know
- Mesh files carry no units, so each format’s convention is applied (glTF/GLB and DAE in metres, FBX and USD in centimetres, STL/3MF/OBJ in millimetres). If a model looks 10×, 25× or 1000× off, switch its File units in the tool — or fix the file for good with the STL scale tool.
- Volume, mass and centre of mass assume a watertight (closed) mesh. Open meshes are flagged; repair them first for reliable numbers.
- STEP and IGES geometry is measured on the tessellated surface (fine deflection), so curved faces are accurate to a small fraction of a millimetre rather than analytically exact.
- Very large meshes (millions of triangles) can take a while to index and use a lot of memory on phones.
FAQ
Questions, answered
Can I measure a STEP file without CAD software?
Yes. The tool reads STEP and IGES files with OpenCascade compiled to WebAssembly, so you can view parts, take dimensions, get volume and mass, and export a parts list — without installing anything and without uploading your file anywhere.
Is my file uploaded to a server?
No. Everything — parsing, tessellation, measuring, sectioning and exporting — runs in your browser. Your model never leaves your device, which matters for confidential CAD.
How do I measure a hole diameter?
Choose Hole ⌀ and click three points spread around the hole’s rim. The tool fits a true 3D circle through them and reports the diameter, so it works on angled faces as well as flat ones.
How is mass calculated?
Mass = closed-mesh volume × the density of the material you pick (common filaments and engineering metals are built in). For an accurate number the mesh must be sealed and the units correct.
How do I calculate the volume of an STL file?
Drop the STL and its volume (cm³ or in³), surface area and bounding box appear in the Dimensions & mass panel — no settings needed. Pick a material to turn the volume into print weight in grams (PLA, PETG, ABS, resin, aluminium, steel, brass…). Volume is computed from the enclosed mesh, not the bounding box, so hollow or shelled parts report their true material volume.
Why is my STL volume zero or obviously wrong?
Two causes. The mesh is not watertight — holes or flipped faces make the enclosed volume undefined; the tool flags open meshes, and STL repair will seal them. Or the units are wrong — an inch file read as millimetres is 16,387× smaller in volume; switch File units or fix the file with the STL scale tool.
Can I get a bill of materials from a STEP assembly?
Yes. Assemblies show a parts list with each part’s name, dimensions, volume and mass. Export it as a CSV BOM for quoting, an RFQ or ERP import, and download any single part as STL or GLB — without opening SolidWorks, Fusion or FreeCAD.
Why does my STL import at the wrong size?
STL, OBJ and 3MF carry no unit information; most slicers assume millimetres, while some CAD exports write inches. If a 50 mm part shows as 1.97 or 1270, change File units in the tool (mm, cm, m, inch) — the dimensions, volume and mass update instantly. To fix the file for good, use STL scale & units.
Is .stp the same as .step?
Yes — both are ISO 10303 STEP files with different extensions; the tool opens .step, .stp, .iges and .igs identically.
Which formats are supported?
STEP (.step/.stp), IGES (.iges/.igs), STL, 3MF, OBJ, GLB/glTF, FBX, PLY, DAE, VRML and USDZ.
Next