Epoxy Calculator
Instantly calculate exactly how much epoxy resin and hardener you need for your project. Perfect for estimating floor coatings, river tables, and deep pours.
1. Project Shape & Dimensions
2. Coating Thickness
3. Product Details
Includes 5% calculated overage.
Whether you are coating a concrete garage floor, creating a thick river table, or resurfacing kitchen countertops, knowing exactly how much epoxy you need is the most critical step of your project. Running out of epoxy mid-pour causes devastating curing lines, while mixing too much results in expensive wasted material.
Our epoxy calculator removes the guesswork. By entering your surface dimensions and your desired coating thickness, it instantly calculates the total liquid volume required. Crucially, it also splits that total volume into exact Part A (Resin) and Part B (Hardener) requirements based on your product’s specific mix ratio.
How to Calculate Epoxy Coverage
Epoxy resin calculations are essentially volume calculations. You must find the total three-dimensional space your coating will occupy. To do this mathematically, the easiest method is to convert all your measurements to inches.
The Epoxy Volume Formula
1. Area (sq inches) = Length (in) × Width (in) 2. Cubic Inches = Area × Thickness (in) 3. Total Gallons = Cubic Inches ÷ 231Why 231? There are exactly 231 cubic inches of liquid volume in one standard US Gallon.
Step-by-Step Calculation Example
Imagine you are pouring a bar top that is 8 feet long and 2 feet wide. You want a standard self-leveling “flood coat” that is 1/8 inch thick (0.125″).
- Convert dimensions to inches: 8 ft = 96 inches. 2 ft = 24 inches.
- Calculate Area: 96 × 24 = 2,304 square inches.
- Calculate Volume: 2,304 × 0.125 = 288 cubic inches.
- Convert to Gallons: 288 ÷ 231 = 1.24 gallons of mixed epoxy.
You would likely purchase a 1.5-gallon kit to ensure you have enough material to account for the epoxy dripping over the edges (waste factor).
Standard Epoxy Coating Thicknesses
The thickness of your pour drastically changes how much material you need. Epoxy thickness is measured either in fractions of an inch or in “mils.” One mil equals 1/1000th of an inch.
| Coating Type | Standard Thickness | Common Use Case |
|---|---|---|
| Seal Coat / Primer | 3 to 5 mils (0.005″) | Sealing porous wood or raw concrete to prevent air bubbles. |
| Roll-On Floor Paint | 10 to 15 mils (0.015″) | Standard garage floor epoxy applied with a paint roller. |
| Flood Coat | 1/8 inch (125 mils) | Self-leveling bar tops, countertops, and metallic marble floors. |
| Deep Pour / Casting | 1 to 2+ inches | River tables, encapsulation, and thick molds. |
How Many Square Feet Will 1 Gallon of Epoxy Cover?
If you prefer a quick reference, the coverage of one mixed gallon of epoxy is entirely dependent on how thick you apply it.
| Applied Thickness | Coverage per 1 Gallon |
|---|---|
| 10 Mils (Thin Roll-on) | ~ 160 square feet |
| 1/16 Inch (62 mils) | ~ 25.6 square feet |
| 1/8 Inch (125 mils) | ~ 12.8 square feet |
| 1/4 Inch (250 mils) | ~ 6.4 square feet |
| 1 Inch Deep Pour | ~ 1.6 square feet |
Mix Ratios: Part A (Resin) vs. Part B (Hardener)
Epoxy only cures when a chemical reaction occurs between the resin and the hardener. You must calculate the exact amounts of each component to ensure a proper cure.
- 1:1 Ratio (Most Common): Used for tabletop and fast-curing epoxies. Simply divide your total needed volume by 2. (Example: For 2 gallons total, mix 1 gal A with 1 gal B).
- 2:1 Ratio (Deep Pours): Used for slow-curing, low-heat casting resins (like river tables). Divide the total volume by 3. Part A is two-thirds of the total; Part B is one-third.
- 3:1 or 4:1 Ratios: Common in marine epoxies and high-performance primers.
Common Epoxy Pouring Mistakes to Avoid
- Not mixing enough material: If you run short on a flood coat, you cannot simply mix a new batch 10 minutes later and pour it next to the old batch. A visible “seam” or line will remain. Always overestimate by 5-10%.
- Ignoring the “Seal Coat”: If you are pouring 1/8″ epoxy over raw, porous wood, the wood will release hundreds of air bubbles into your thick pour as it cures. You must calculate and apply a thin seal coat first, let it tack up, and then apply your flood coat.
- Scraping the bucket: When you pour your mixed epoxy onto the surface, do not aggressively scrape the sides and bottom of your mixing bucket. Unmixed resin clings to the plastic sides; scraping it out will result in soft, sticky spots on your floor or table that will never cure.
Frequently Asked Questions
Reference: https://en.wikipedia.org/wiki/Epoxy