Casting Weight Calculator

Estimate finished metal weight from model volume or from a wax/resin pattern weight.

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What this tool does

Estimates the weight of the finished casting from the model’s volume (for example from CAD or an STL) or from the weight of a wax or resin pattern.

When to use it

Use it to estimate metal needed for a pour, quote a casting, or check a CAD model against your metal budget.

What each input means

Model volume
From your CAD software or the volume shown on a design page. mm³ ÷ 1000 = cm³.
Pattern weight
Weight of the wax or resin model before investing.
Allowance %
Optional extra for sprue and process loss; leave at 0 for the piece only.

Formula and method

  • From volume: metal weight = volume (cm³) × metal density × (1 + allowance)
  • From pattern: metal weight = pattern weight × (metal density ÷ pattern density) × (1 + allowance)

Worked example

Two ways to the same kind of answer:

  1. Volume: 1,000 mm³ = 1 cm³ of 18K (≈15.5 g/cm³) → 15.5 g
  2. Wax: 1 g of wax at 0.95 g/cm³ cast in 14K (≈13.0 g/cm³) → 1 × 13.0 ÷ 0.95 = 13.68 g

Calculated estimates: 15.5 g and 13.68 g

Limitations

  • Calculated estimate — real castings vary with alloy, porosity, shrinkage and finishing.
  • Wax and resin densities vary by product; enter your product’s density for best results.
  • Sprues, buttons and runners are not included unless you add an allowance.

Frequently asked questions

How do I estimate casting weight from wax?
Multiply the wax weight by the ratio of metal density to wax density. This calculator does that for you and lets you change the wax density.
Why is my finished piece lighter than estimated?
Finishing removes metal, and castings can contain micro-porosity.

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