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
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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