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This epoxy floor calculator estimates how much epoxy coating you need for a garage, basement or shop floor. Enter the floor area, the number of coats, the dry film thickness and the volume solids from the product data sheet, and it calculates gallons and kits.
How to Use the Epoxy Floor Calculator
- Measure the floor area (a typical one-car garage is about 250 sq ft and a two-car garage about 400–500 sq ft).
- Enter the number of coats you plan to apply.
- Enter the dry film thickness per coat in mils (thousandths of an inch).
- Enter the volume solids from the product label (100% for solvent-free epoxy, often 40–60% for water-based products).
Epoxy Coverage Formula
Coverage (sq ft per gallon) = 1,604 × Volume solids ÷ Dry film thickness (mils)
A US gallon is 231 cubic inches. Spread 1 mil thick, it covers 1,604 sq ft. The solvents or water in a coating evaporate, so only the solids remain as the dry film.
Example
A 400 sq ft garage with two coats of 100% solids epoxy at 10 mils each needs 2.5 gallons per coat. With 15% extra for porous concrete, that is about 5.7 gallons, or two 3-gallon kits.
Typical Coverage by Thickness
| Dry film per coat | 100% solids | 50% solids |
|---|---|---|
| 3 mils | 535 sq ft/gal | 267 sq ft/gal |
| 5 mils | 321 sq ft/gal | 160 sq ft/gal |
| 8 mils | 200 sq ft/gal | 100 sq ft/gal |
| 10 mils | 160 sq ft/gal | 80 sq ft/gal |
| 16 mils | 100 sq ft/gal | 50 sq ft/gal |
| 20 mils | 80 sq ft/gal | 40 sq ft/gal |
Tips for an Epoxy Garage Floor
- Grind or acid-etch the concrete so the coating can bond.
- Test for moisture by taping plastic sheet to the slab for 24 hours.
- Mix only what you can apply within the pot life printed on the kit.
- Add decorative flakes and a clear topcoat for durability and grip.
Frequently Asked Questions
How much epoxy do I need for a 2-car garage?
A 400–500 sq ft two-car garage needs about 2.5–3 gallons per coat of 100% solids epoxy at 10 mils, or about 5–7 gallons for two coats with waste.
How many square feet does a gallon of epoxy cover?
At 10 mils, 100% solids epoxy covers about 160 sq ft per gallon. Thinner water-based coatings cover 250–400 sq ft per gallon.
How thick should a garage floor epoxy be?
DIY kits are typically applied at 3–10 mils per coat; professional systems total 20 mils or more.
What does volume solids mean?
It is the percentage of the coating that stays on the floor after drying. The rest evaporates.
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