Resin Casting Volume Calculator
Calculate how much epoxy resin and hardener you need for casting molds.
Enter mold dimensions to get exact mixing ratios.
Resin Casting Volume is calculated from the mold dimensions, then split into resin and hardener based on the mixing ratio.
Volume calculation for common mold shapes:
Rectangular/cube molds:
Volume = Length × Width × Height
Cylindrical molds:
Volume = π × Radius² × Height
Converting volume to weight: Epoxy resin has a specific gravity of approximately 1.1-1.2, meaning 1 cubic inch weighs about 0.6 ounces (17 grams), and 1 cubic centimeter weighs about 1.1-1.2 grams.
Common mixing ratios (by volume):
- Most craft epoxies: 1:1 (equal parts resin and hardener)
- Some industrial epoxies: 2:1 (two parts resin to one part hardener)
- Polyester resin: 100:1 to 100:2 (resin to catalyst by weight)
- Polyurethane resin: 1:1 by volume
Important considerations:
- Always mix 10-15% extra to account for mixing cup residue and small spills
- Temperature affects curing time: warmer = faster cure, cooler = slower cure
- Working time (pot life) ranges from 15-45 minutes for most craft epoxies
- Pour in layers for pieces thicker than 1 inch (2.5 cm) to prevent overheating
- Exothermic reaction: thick pours generate heat and can crack or yellow
Weight conversion (imperial):
- 1 cubic inch of epoxy ≈ 0.6 oz (17g)
- 1 fluid ounce ≈ 1.8 cubic inches
Weight conversion (metric):
- 1 cubic centimeter of epoxy ≈ 1.1 grams
- 1 milliliter ≈ 1 cubic centimeter
Pro tip: Use a digital scale for accurate measurements. Volume measurements with cups are less precise and can cause improper curing.