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 {#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
is the mix ratio (e.g., 2 means R=2, H=1).Mix Ratio Guide {#mix-ratio}
| Ratio | Common Use | Resin % |
|---|---|---|
| 1 | Table tops, art resin, casting | 50% |
| 2 | Marine, structural, boat building | 67% |
| 3 | Fiberglass laminating, some casting resins | 75% |
Always check your specific resin product's data sheet. Incorrect ratios prevent proper curing.
Tips for Epoxy Projects {#tips}
- 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.
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Construction & Engineering Notice
This calculator is for general estimation purposes only.
- Results are approximations and do not account for waste, cuts, settling, code requirements, or site-specific conditions.
- Always verify quantities and structural requirements with a qualified contractor, engineer, or local building authority.
- Consult applicable building codes (e.g. IBC, local regulations) and order extra material to account for waste before construction.