Epoxy Floor Calculator
This epoxy floor calculator works out how much epoxy you need to coat a garage, basement, or shop floor. Enter the floor size, the thickness per coat in mils, the number of coats, and the solids content, and the epoxy floor calculator returns the gallons, liters, kits, and coverage per gallon, with a waste allowance included.
Results
The Epoxy Floor Calculator is part of our Floor & Wall collection. Browse more floor & wall to size, convert, and check your work alongside this tool.
What the epoxy floor calculator does
Epoxy coverage depends on how thick you apply it. One US gallon spread 1 mil thick, a thousandth of an inch, covers 1,604 square feet. The epoxy floor calculator divides that figure by your film thickness to get the coverage per gallon, adjusts for the solids content because solvent and water evaporate, multiplies by the floor area and the number of coats, and adds waste. The result is the gallons to buy and the number of kits.
Epoxy coverage per gallon formula
A gallon holds 231 cubic inches, which spread 1 mil thick covers 1,604.17 square feet:
Kits needed is the gallons divided by the kit size, rounded up. Mils here means the dry film you want; lower solids need more wet material to leave the same dry film.
Epoxy floor calculator example
A 20 × 20 ft garage floor, two coats at 10 mils, 100% solids, and 10% waste:
That is 20.77 liters, or six 1 gallon kits. With a 50% solids product the same floor needs 10.97 gal. A 24 × 24 ft floor with a 1/8 in self leveling coat needs 49.37 gal, or 17 three gallon kits.
How to use the epoxy floor calculator
Enter the floor length and width in feet. Enter the wet film thickness per coat in mils from the product data sheet: thin roll coats run 3 to 10 mils, high build coats 10 to 20 mils, and self leveling coatings 1/8 in, which is 125 mils. Enter the number of coats and the solids percentage, 100% for most garage floor epoxies, then the waste allowance and the kit size. Press Calculate.
Reading epoxy coverage per gallon
The coverage per gallon tells you how far one gallon goes at your thickness; compare it with the spread rate on the product label. The gallon total covers every coat plus waste. Concrete that is porous, freshly ground, or shot blasted soaks up the first coat, so many installers add 10 to 20% more for the primer coat. Flakes and topcoats are separate products, so size them with their own spread rates.
When to use a garage floor epoxy calculator
- Buying epoxy kits for a garage floor
- Pricing a basement or shop floor coating
- Comparing thin roll coats with self leveling systems
- Checking a contractor quote for material
- Planning primer, body, and top coats
Common epoxy floor calculator mistakes
- Using inches for mils. 1/8 inch is 125 mils, not 0.125.
- Ignoring solids. Water based epoxies may be 40 to 60% solids.
- One coat in the math. Count primer, body, and top coats.
- No porosity allowance. Ground concrete soaks up extra material.
Tips for epoxy floor coverage
- Mark the floor in sections sized to one kit for even spread.
- Use a notched squeegee set to your target mils.
- Apply in the temperature range on the label for proper cure.
Epoxy mils and floor thickness explained
A mil is a thousandth of an inch, about 0.025 mm, the thickness of a sheet of plastic wrap. Floor coatings are specified in mils because the numbers stay simple: a thin sealer might lay down 3 mils, a good roll coat 10, and a self leveling system 125 or more. Thickness drives durability. Thin coats look good but wear through at tire paths and under dropped tools, while thicker films resist chips and hot tire pickup. The same thickness drives material use, so a 125 mil pour takes about twelve times the epoxy of a 10 mil roll coat. Many systems combine coats: a penetrating primer at 4 to 6 mils, a body coat with color flakes at 10 to 15 mils, and a clear urethane or polyaspartic topcoat. Run each layer through the epoxy floor calculator with its own thickness and solids.
How much epoxy for floor prep and porosity
Most epoxy failures start with preparation, not the coating. New concrete should cure for about 28 days, and every slab needs a moisture test, since vapor coming up through the slab pushes coatings off. Grinding or shot blasting opens the surface so the primer bonds, and that rough profile holds more material than a smooth test panel, which is why a waste allowance of 10% or more is wise on the first coat. Check the slab size and any thickness change first with the concrete calculator if you are pouring new, and mix only what you can apply within the pot life printed on the kit.
Epoxy coverage chart
Coverage per gallon per coat at common thicknesses, for 100% and 50% solids products:
| Thickness | 100% solids | 50% solids |
|---|---|---|
| 3 mils | 534.7 sq ft | 267.4 sq ft |
| 5 mils | 320.8 sq ft | 160.4 sq ft |
| 8 mils | 200.5 sq ft | 100.3 sq ft |
| 10 mils | 160.4 sq ft | 80.2 sq ft |
| 15 mils | 106.9 sq ft | 53.5 sq ft |
| 20 mils | 80.2 sq ft | 40.1 sq ft |
| 125 mils (1/8 in) | 12.8 sq ft | 6.4 sq ft |
Epoxy Floor Calculator FAQ
How much epoxy do I need for my garage floor?
A two car garage of about 400 sq ft needs about 5 gallons of 100% solids epoxy for two 10 mil coats, or 5.49 gallons with 10% waste.
How many square feet does a gallon of epoxy cover?
At 100% solids a gallon covers 1,604 sq ft divided by the thickness in mils: 160 sq ft at 10 mils and about 12.8 sq ft at 1/8 inch.
What thickness should a garage floor epoxy be?
Residential garage systems usually build 10 to 20 mils per coat. Heavy traffic and industrial floors often use self leveling coatings of 1/8 inch or more.
Why does solids content matter?
Solvent and water evaporate after you apply them. A 50% solids product leaves half its wet thickness, so you need twice as much material for the same dry film.