Resin Pour Calculator
Calculate epoxy resin and hardener for molds, coatings, and river tables from dimensions and pour depth.
Returns part A and part B at 1:1 or 2:1 ratio.
Epoxy resin volume calculation determines exactly how much mixed resin (Part A resin + Part B hardener) you need to fill a mold, coat a surface, or complete a pour art project. Resin is sold and mixed by volume or weight depending on the product.
Volume formula (rectangular mold): Volume (mL) = Length (cm) × Width (cm) × Depth (cm)
Volume formula (round/cylindrical mold): Volume (mL) = π × Radius² × Depth (cm)
Converting cubic centimeters to mL: 1 cm³ = 1 mL — they are identical units.
Mix ratio formula (by volume): Most epoxy resins use 1:1 or 2:1 (A:B) by volume ratios.
For 2:1 ratio (2 parts resin : 1 part hardener):
- Part A (resin) = Total Volume × (2 ÷ 3)
- Part B (hardener) = Total Volume × (1 ÷ 3)
Overage factor: Always add 10–15% overage — resin loses volume to container walls, mixing sticks, and spills. Shallow pours may need 20% extra for surface leveling.
Weight from volume: Weight (g) = Volume (mL) × Specific Gravity Typical epoxy specific gravity: 1.1–1.2 g/mL
What each variable means:
- Depth of pour — maximum single-layer depth is typically 1/4 inch (6mm) for casting resins. Deep pours require layered curing to prevent exothermic cracking.
- Exothermic reaction — mixing resin generates heat. Deep pours in confined molds can crack, yellow, or even catch fire if maximum pour depth is exceeded.
- Cure time vs hardener type — slow hardeners (24–72 hr) allow bubbles to escape; fast hardeners (2–4 hr) trap bubbles but work faster.
Reference: resin volumes for common projects
- Coaster (4 in round, 1/4 in deep): ~130 mL
- Small tray (8 in × 12 in × 1/4 in): ~590 mL
- River table (6 ft × 3 ft × 1 in, center channel only): ~17,000 mL = 17 liters
- Tumbler coating (1 layer): ~30–60 mL
Worked example: Rectangular mold: 20 cm × 30 cm × 2 cm deep. Using 2:1 ratio epoxy.
Total volume = 20 × 30 × 2 = 1,200 mL With 12% overage = 1,200 × 1.12 = 1,344 mL total needed
Part A = 1,344 × 2/3 = 896 mL resin Part B = 1,344 × 1/3 = 448 mL hardener
Weight = 1,344 mL × 1.15 g/mL = 1,545.6 g ≈ 1.55 kg of mixed resin