Casting Weight Calculator
Estimate the net cast weight of a part from its shape and alloy — then get the poured (melt) weight, batch quantity and material cost. Unlike generic metal calculators, this one uses real cast-alloy densities (cast 304/316, gray and ductile iron, bronze, A356) and lets you enter a CAD volume for complex castings.
How casting weight is calculated
Weight = part volume × alloy density. Volume comes from the geometry you choose, or directly from your CAD model:
The poured weight includes the gating and feeders that are remelted — it is what actually determines melt cost. Net weight is the finished part.
Cast-alloy density reference
| Alloy | Density (g/cm³) |
|---|---|
| Carbon / low-alloy steel | 7.85 |
| Cast stainless 304 (CF8) | 7.93 |
| Cast stainless 316 (CF8M) | 7.98 |
| Gray cast iron | 7.20 |
| Ductile (nodular) iron | 7.10 |
| Bronze (general) | 8.80 |
| Yellow brass | 8.50 |
| Aluminum A356 | 2.68 |
1 g/cm³ = 1000 kg/m³ = 0.0361 lb/in³. Use a custom density for alloys not listed.
Frequently Asked Questions
How do you calculate the weight of a casting?
Multiply the part’s volume by the alloy density. Get the volume from the geometry (length, diameter, etc.) or directly from a CAD model, then multiply by the density — for example 7.85 g/cm³ for carbon steel or 7.20 for gray iron.
What is the difference between net weight and poured weight?
Net weight is the finished casting. Poured (melt) weight also includes the gating, runners and risers that feed the mould and are later remelted. Poured weight = net weight ÷ casting yield, where yield is typically 50–70% for investment casting.
What density should I use for cast stainless steel?
Cast stainless grades differ slightly from wrought: use about 7.93 g/cm³ for cast 304 (CF8) and 7.98 for cast 316 (CF8M). Generic “stainless” values from metal calculators can be off for castings.
Can I calculate weight from a CAD volume?
Yes. Switch the shape selector to “Custom Volume” and enter the volume from your CAD model in cm³ or in³; the calculator multiplies it by the alloy density. This is the most accurate option for complex castings.
Why is the actual casting heavier than calculated?
As-cast parts include machining stock, draft and tolerance, and the density assumes zero porosity. Treat the result as a close estimate and confirm with a first-article weight.
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