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Redmoon Calculators
Maker & workshop

Resin & Epoxy Cost Calculator

Free resin and epoxy cost calculator. Enter mold dimensions (rectangular or cylinder), resin price per gallon, density, waste percentage, additives, and amortized mold cost; outputs the exact volume, weight, and total cost per pour.

Built and maintained by Paul Clark, Redmoon Software

When to use this

Use before pricing a resin piece for sale, or when comparing whether a cheaper bulk resin or a different mold-amortization schedule meaningfully changes your per-piece cost.

How it compares

Like the 3D Print Cost & Profit Estimator, this converts a physical volume into a material cost, but resin's waste percentage and mold amortization play the role that 3D printing's failure buffer and printer wear play.

Enter your values below. Calculations run locally as you type.

Mold & resin

Cost per pour

Volume needed
0.107 gal
24.0 in³ incl. 3% waste
Weight
0.97 lb
@ 9.1 lb/gal
Resin cost
$4.82
0.107 gal × $45.00
Total cost
$6.72
+ additive $1.50 + mold/use $0.40

This pour needs about 13.7 fl oz of mixed resin.

How it works

Volume is computed from mold dimensions — length × width × depth for rectangular molds, or π × (diameter ÷ 2)² × depth for cylinders — converted from cubic inches to gallons by dividing by 231.

A waste/cure-loss percentage is added on top to cover mixing cup residue and stir-stick drag, then converted to weight using resin density in lb/gallon.

Total cost = resin cost (volume × price per gallon) + flat additive/pigment cost + mold cost amortized over its expected number of uses.

FAQs

How do I measure a mold's volume in practice?

Fill the empty mold with water and measure the poured volume in a graduated cup, or use the dimension formula this calculator applies — length × width × depth for rectangular molds, or π × (diameter ÷ 2)² × depth for cylinders.

Why does real resin usage always run a bit more than the "gallon price" suggests?

Mixing cup residue, stir-stick drag, and trimmed overflow all add loss beyond the mold's exact volume. The waste/cure-loss percentage field bakes that overage into the total.

Do 1:1 vs 2:1 epoxy mix ratios change my cost?

The mix ratio doesn't change the poured volume, but different ratios come in differently sized part-A/part-B bottles, which can shift your effective price per gallon — enter the actual price you pay per gallon of combined mixed resin.

Worked example

Input

Rectangular mold 6" × 4" × 1", $45/gallon resin, 9.1 lb/gal density, 3% waste, $1.50 additive, $20 mold amortized over 50 uses.

Output

Volume 0.107 gal (24 in³) → total cost $6.72.

24 cubic inches converts to 0.104 gallons, plus 3% waste brings it to about 0.107 gallons weighing roughly 0.97 lb. Resin cost is $4.82, plus $1.50 additive and $0.40 mold-per-use ($20 ÷ 50 uses), for a total pour cost of about $6.72.

Common pitfalls

  • Volume formulas assume a filled solid — subtract cavity volume yourself if the mold has voids or inserts.
  • Resin density varies by brand and formulation — check your specific product's data sheet rather than trusting the default.
  • Doesn't include cure time or labor — add that separately if you charge for your working time.

Resin printing costs more than the resin

Per-millilitre resin cost is the obvious input and rarely the largest. Resin printing adds consumables that FDM does not have: isopropyl alcohol for washing, which is consumed steadily and is not cheap; nitrile gloves for every handling step; paper towels and filters; and the FEP or nFEP film in the vat, which is a wear item replaced on a schedule.

Post-processing is also compulsory rather than optional. Wash and cure time is real labour on every print, not just on the ones that need finishing.

Supports, failures and safe handling

Support material on a resin print is frequently a large fraction of total volume — often comparable to the model itself on an organic shape — and it is consumed whether or not the print succeeds. Cost per model should be computed on total resin used, not on the model's own volume.

Uncured resin is a sensitiser and an irritant, and repeated skin exposure can produce an allergy that ends the hobby. Waste resin and contaminated alcohol must be cured before disposal rather than poured away. None of that is a cost line, but it is the part of the process that most affects whether it is worth doing at home.

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