Epoxy Resin Calculator
This epoxy resin calculator computes exactly how much resin and hardener you need. Enter the surface length, width, and depth in inches, select your mix ratio (1:1, 2:1, or 3:1), and get the total fluid ounces with resin and hardener split separately. A 12×12 inch, ⅛-inch-deep pour needs approximately 9.97 fl oz of mixed epoxy.
Result
Frequently Asked Questions
How much epoxy resin do I need?
Multiply length × width × depth (all in inches) to get cubic inches. Then multiply by 0.554 to get fluid ounces of mixed epoxy. For example, a 12×12 inch surface with 1/8 inch depth: 12×12×0.125 = 18 cubic inches × 0.554 = 9.97 fl oz total.
What is epoxy mix ratio?
Epoxy mix ratio is the proportion of resin (part A) to hardener (part B). A 1:1 ratio means equal parts of each. A 2:1 ratio means 2 parts resin to 1 part hardener. The ratio must be precise — measuring by volume is most common, though some professional resins require measurement by weight.
How many ounces of epoxy for a 12x12 table top?
For a 12×12 inch table top at 1/8 inch depth: 18 cubic inches × 0.554 = 9.97 fluid ounces. At 1/4 inch depth: 36 cubic inches × 0.554 = 19.94 fl oz. Always add 10–15% extra for drips and waste.
What is the difference between 1:1 and 2:1 epoxy?
1:1 epoxy (equal parts resin and hardener) is common for art projects, table tops, and casting. It's generally easier to measure. 2:1 epoxy (2 parts resin, 1 part hardener) is used in marine and structural applications and often produces a harder, more chemical-resistant cure.
How thick should I pour epoxy in one pour?
Most table-top and art resins have a maximum pour depth of 1/4 inch per layer. Pouring too thick causes exothermic heat buildup, which can crack or yellow the resin. For thick river tables or deep castings, use a casting resin rated for deep pours (up to 2–4 inches), or build up in 1/4 inch layers with 24 hours between pours.
How do I prevent bubbles in epoxy?
Mix slowly to avoid introducing air. After pouring, lightly pass a heat gun or propane torch 6–8 inches above the surface — the CO₂ in your breath pops bubbles. Warm the resin slightly before mixing (70–80°F) to reduce viscosity and help bubbles escape more easily.
How long does epoxy take to cure?
Most epoxy resins are tack-free after 24 hours and reach full hardness after 48–72 hours at 75°F (24°C). Cold temperatures slow curing significantly. Do not use the surface before full cure. The pot life (working time after mixing) is typically 20–45 minutes depending on the product.
Can I use epoxy outdoors?
Most epoxy resins yellow when exposed to UV light, so outdoor or window-facing applications require a UV-resistant topcoat or a UV-stabilized epoxy formula. Marine epoxies are specifically designed for outdoor durability. Always check the manufacturer's specifications for UV resistance.
Epoxy Resin Formula
To calculate how much epoxy resin you need, multiply the surface dimensions to get cubic inches, then convert to fluid ounces using the density of cured epoxy (≈ 0.554 fl oz per cubic inch).
Volume (in³) = Length × Width × Depth
Total oz = Volume × 0.554
Resin oz = Total oz × (R / (R + H))
where R:H is the mix ratio (e.g., 2:1 means R=2, H=1)
Mix Ratio Guide
| Ratio | Common Use | Resin % |
|---|---|---|
| 1:1 | Table tops, art resin, casting | 50% |
| 2:1 | Marine, structural, boat building | 67% |
| 3:1 | Fiberglass laminating, some casting resins | 75% |
Always check your specific resin product's data sheet. Incorrect ratios prevent proper curing.
Tips for Epoxy Projects
- Add 10–15% extra — Account for mixing losses, drips, and surface irregularities.
- Temperature matters — Epoxy cures faster in warm conditions. Most resins require 70–80°F (21–27°C) for proper cure.
- Pour in layers — For depths over ¼ inch, pour in multiple ¼-inch layers to prevent exothermic cracking.
- Mix thoroughly — Scrape the sides and bottom of the container. Undermixed resin stays sticky permanently.
- Pot life vs. cure time — Pot life (working time) is 20–45 min for most resins. Full cure takes 24–72 hours.
Related Tools
- Aquarium Volume Calculator — Volume of tanks in gallons and liters
- Paint Calculator — Calculate paint needed for walls and surfaces