Mold & Resin Calculator

How much silicone or resin to mix, split by ratio, with shrinkage compensation for accurate castings.

Volume needed

Cavity / container shape

Subtract object volume (optional, cm³)

Total volume

enter dimensions

Fluid ounces

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+10% waste

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Two-part mix

Ratio (A : B)

Ratio by

Material density (g/cm³) — for weight

Part A

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Part B

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Uses the +10% volume so you don't come up short mid-pour. Always confirm the exact ratio on your product's datasheet.

Shrinkage compensation

Shrinkage (%)

Target final size

Make your pattern this size

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Scale the master pattern up so the casting shrinks to your target. Pattern = final ÷ (1 − shrink%).

Mold-makers and casters on The Spool List — escrow-protected.