Silicone mould quantity calculator
Estimate mixed silicone from your mould-box dimensions and measured model displacement.
How to use this calculator
- Measure inside the container to your planned fill height, including coverage above the model.
- Measure object displacement separately. A graduated vessel’s rise in liquid can work for a compatible sealed model; do not wet absorbent or damageable models.
- Add an allowance for spills or material left in cups if needed. Use the result with your exact silicone product’s recipe.
Worked example
A box measuring 12 × 10 cm internally, filled 5 cm high, holds 600 mL. Models displacing 180 mL leave 420 mL silicone per mould. For 2 identical moulds plus a chosen 10% allowance: (600 − 180) × 2 × 1.10 = 924 mL mixed silicone.
Questions about this calculation
Can I use the model’s length × width × height as displacement?
Only if it is actually a solid rectangular block. A bounding box overestimates the displacement of irregular models and underestimates the silicone required. Enter a measured volume for the submerged portion of the model, including any fixtures that occupy the fill space.
How do I calculate a round mould box?
Use the inside diameter and planned fill height. Container volume is π × (diameter ÷ 2)² × height. The tool then subtracts your measured object displacement; it does not treat the model as a cylinder.
How many grams of silicone is this?
Multiply mixed volume in mL by the exact product’s mixed density in g/mL. Generic silicone has no universal density. The Mold Star 30 tool can use its published density after you transfer your volume.
Sources and measurement basis
Use the exact current instructions for your product, version and market. Review date: 16 October 2026.