Weight and cost from the same model
Get dimensions of an STL file in the Info panel
| Line | Units | Use it for |
|---|---|---|
| X (width), Y (depth), Z (height) | mm or in | does it fit the bed, the box, the assembly |
| Volume | cm³ or in³ | weight, material, resin needed |
| Surface area | cm² or in² | paint, coating, sanding time |
| Triangles, vertices, parts | count | how heavy the mesh is, how many loose bodies |
| Weight and cost | g, your currency | quotes and spool planning |
| Mesh check | yes / no, counts | whether the volume can be trusted |
The mm / in button in the header switches every length between millimetres and inches.
How to measure an STL file step by step
- Drop the STL on the viewer, or press Open File. STEP, 3MF, OBJ and the other formats the viewer reads work the same way.
- Open Info and read the overall size and the volume.
- Press Measure and click two points on the model. The distance and its ΔX, ΔY and ΔZ parts appear next to the line.
- For a wall or a bore, open Section, slide the plane through the part and measure across the red cut face.
The model is read by the browser tab itself. Measuring a client's part does not send it anywhere.
Point-to-point measuring with vertex snap
The Measure tool snaps to the nearest vertex, so a click on a corner lands exactly on it. Hold Alt to turn snapping off and pick a point in the middle of a face. In the test, two corners of the 20 mm cube measured exactly 20.00 mm.
The ΔX, ΔY and ΔZ readout helps with offset features: the height of a boss above a plate, or the spacing of two holes along one axis.
Millimetres, inches and the units note
STL, OBJ and PLY carry no units. The viewer shows their numbers as millimetres, and a part drawn in inches therefore looks tiny. A 2 inch bracket reads 2 mm, and you notice only when the slicer shows a speck on the bed. Edit → Size → Inches → mm fixes it; the scale STL page walks through it.
STEP and IGES declare a unit, and the viewer converts it to millimetres: a 1 inch cube declared in inches reads 25.4 mm. Some exporters label millimetre numbers as inches; the AS1 test assembly then reads 5080 mm, the viewer warns Check the units, and the switch Numbers are millimetres gives the intended 200 × 87 × 150 mm. COLLADA keeps its unit too: a Maya file in centimetres reads 800 × 1800 × 693 mm.
The box size depends on how the part sits
X × Y × Z is the bounding box along the three axes. A bracket that lies at 45° reports a bigger box than its true length. Turn it square under Rotate, mirror, move in the STL editor, and the box then matches the part's real length.
Volume is only meaningful for a closed mesh. If the mesh check shows holes or open edges, fix them first, then read the volume again.
From size to weight, cost and print time
The same Info panel turns the volume into weight for 17 materials and into a print price. The two pages below go deeper: the filament calculator covers densities and grams, and the 3D print cost calculator covers the price formula.
For the hours, open the G-code from your slicer on print time. If you want the background on what drives the price of a print, read what 3D printing costs.
Questions and answers
How do I get the dimensions of an STL file without CAD?
Open it in the viewer above. Info shows X × Y × Z right away, in mm or inches, with volume and surface area under it.
Why is my STL 25.4 times too small?
It was drawn in inches, and STL stores no units. Press Edit → Size → Inches → mm (×25.4).
How accurate is the measure tool?
It snaps to vertices of the mesh, so it is as accurate as the mesh itself. Two corners of the 20 mm test cube read exactly 20.00 mm.
Can I measure STEP and 3MF files too?
Yes. STEP and IGES are converted from their declared unit to millimetres. 3MF records its unit in the file, millimetres by default.
Can I see the size in inches instead of millimetres?
Press the mm / in button in the header. Lengths switch to inches, volume to in³ and area to in², and the model itself is not changed.
Why does the volume of my model look wrong?
Either the mesh is open, so it has no clear inside, or the units are off. Check the watertight line in Info and the size of the part before you trust the volume.
Does it work on a phone?
The page layout is tested at 390 px width with no sideways scrolling. Orbit, zoom and pan work with touch.