Materials calculator

3D Part Weight Calculator

Upload a STEP file and get its weight from the modeled solid volume and the material you pick, all in your browser.

Upload a STEP part for its actual modeled weight

We read exact solid volume from the model, so holes, cutouts, and bends are included. Choose a material to calculate its weight.

Drop a STEP file here

.stp or .step, up to 24 MB. Nothing is uploaded.

Part weight

Upload a part to see its modeled weight and a body-by-body breakdown.

Ready to manufacture this part? Upload the STEP file in the quote builder for Fabworks manufacturability feedback, pricing, and lead time.

Quick answer

How it works

Weight is the volume of the solid in your STEP file times the density of the material. Holes, cutouts, and bends are already in that volume, so you do not enter any dimensions. One density applies to the whole file, so an assembly of mixed materials will come out wrong.

How to use the calculator

  1. 1Export the part from your CAD program as a STEP solid (AP214 or AP242). A surface model has no volume.
  2. 2Drop the file in and pick the material. The Fabworks list has the alloys we cut, All materials has the rest, and Custom takes a density from a mill cert.
  3. 3If the file has more than one body, read the list. Each solid is weighed and added to the total, including any screws or nuts in the export.
  4. 4Compare the total with your CAD program. If it is off by about 25 or 1000 times, the export used the wrong units.

Worked example

Steel bracket plate

Inputs
A 6 × 4 × 0.125 in plate with four 0.25 in holes, exported as STEP and weighed as A36 steel (7,861 kg/m³).
Result
Solid volume = 2.975 in³ and weight = 0.845 lb.

The blank is 3.000 in³ and the four holes take out 0.025 in³. 2.975 in³ × 0.284 lb/in³ = 0.845 lb.

Common questions

What to know before using the result

Is my STEP file uploaded?
No. The file is read in your browser and never sent to us. Starting a quote is a separate step.
Why does my STEP file fail?
It has no closed solid. Surface-only models and open shells have no volume. Re-export from your CAD program as a solid body. Files over 24 MB are rejected.
Does the weight include coating or hardware?
Only what is modeled. Paint and powder coat are not in the volume, and neither is any hardware that is not in the file.
Why is my CAD program showing a different weight?
Usually density. Your CAD program weighs with the material assigned in that file, and this page ignores it and uses the material you pick. Match the density first, then look at units and extra bodies.

Formula

m = V × ρ

Your browser reads the volume of each solid in the STEP file and multiplies it by the density you pick.

Engineering references

Assumptions and limits

  • The file needs at least one closed solid. Surface models and open shells have no volume.
  • One density is applied to every body in the file.
  • Coating, paint, and hardware that is not modeled are not counted.
  • Densities are typical values for each alloy. Use Custom if you have a mill cert.

Keep designing

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