Epoxy Floor Calculator
Garage floor epoxy estimate: number of DIY kits, or gallons by mil thickness, solids and coats — plus decorative flakes for any broadcast.
Your estimate
2 kits
Kits needed (incl. 10% loss)
- Floor area
- 440 sq ft
- Flakes
- 2.2 lb
Show the math
- Area = 440 sq ft × 1 coat
- × (1 + 10%) = 484 sq ft
- ÷ 250 sq ft per kit → 2 kits
- Flakes = 440 sq ft ÷ 200 sq ft per lb = 2.2 lb
Shopping list & cost
| Item | Spec | Qty | Cost |
|---|---|---|---|
| Garage floor epoxy kit | 250 sq ft per kit, 1 coat | 2 kits | — |
| Decorative flakes | light sprinkle (typical diy-kit look), ≈ 200 sq ft per lb | 2.2 lb | — |
| Concrete etch or diamond grinding | profile CSP 2–3 so the coating can bond | 440 sq ft | — |
| Degreaser, crack filler, ⅜ in nap rollers, spiked shoes | prep and application | 1 set | — |
Prices are what you enter under Advanced options. Estimates only — check stock and pricing with your supplier.
Quick answer A 22 × 20 ft two-car garage (440 sq ft) needs 2 kits of a typical DIY epoxy coating rated at 250 sq ft per kit, allowing 10% for porous concrete, and 2.2 lb of flakes for a light sprinkle. A 6.5 × 6 m garage needs 2 kits at 23 m² per kit. Buying bulk instead? A gallon of 100% solids epoxy covers 160 sq ft at 10 mils dry: coverage = 1,604 × solids ÷ mils.
Method & assumptions
Kits = Area × Coats × (1 + loss %) ÷ Kit coverage Coverage (sq ft/gal) = 1,604 × Volume solids ÷ Dry mils Gallons = Area × Coats ÷ Coverage × (1 + loss %) Wet mils = Dry mils ÷ Volume solids Flakes (lb) = Area ÷ broadcast rate (sq ft per lb)
- 1,604
- sq ft one US gallon covers at 1 mil (0.001 in) thick
- Volume solids
- share of the liquid that remains as film: 100% for solvent-free epoxy, ~40–60% for water-based
- Broadcast rate
- light 200, medium 60, heavy 25, full ≈ 7 sq ft per lb (¼ in flake)
Assumptions & limits
- Kit coverage is per coat as printed on the box; typical 1-car kits are about 250 sq ft and 2-car kits about 500 sq ft.
- Bulk estimate applies the same dry film to every coat; primers and topcoats are often thinner — run them separately if needed.
- Flake rates are typical for ¼ in vinyl chip; makers quote 20–250 sq ft/lb for partial and 5–10 sq ft/lb for full broadcast.
- The slab must be clean, profiled and dry — moisture coming up through the concrete is the main cause of failures.
Rounding: purchase quantities are always rounded up to whole units as sold. See our methodology.
Diagram
How to use this calculator
- Measure the floor; include the apron if you are coating it.
- Choose how you are buying: DIY kits (coverage is on the box) or bulk epoxy by thickness.
- For bulk, enter the volume solids from the data sheet and the dry film thickness and coats you want.
- Keep 10% for porous or ground concrete and roller loss; use 15–20% on rough, thirsty slabs.
- Choose a flake broadcast — the difference between a light sprinkle and a full broadcast is more than 25× the flakes.
Worked examples
Imperial: 24 × 24 ft garage, 100% solids epoxy, 10 mil base + 10 mil top
- Coverage = 1,604 ÷ 10 = 160 sq ft/gal per coat
- 576 × 2 ÷ 160.4 = 7.2 gal; +10% = 7.9 gal
Imperial: 22 × 12 ft single garage, DIY kits at 250 sq ft
- 264 sq ft × 1.10 = 290 sq ft
- ÷ 250 = 1.16 → 2 kits (a single "1-car" kit is not quite enough)
In depth: epoxy floor planning notes
Kits, gallons and mils
DIY garage floor kits are rated by area per kit — typically about 250 sq ft for a "1-car" kit and 500 sq ft for a "2-car" kit — and most are designed to go on as one coat. Concrete is porous, especially after etching or grinding, so the calculator adds 10% before dividing by the kit coverage: a 22 × 12 ft single garage is 264 sq ft and already needs two 250 sq ft kits. If the slab is very rough or thirsty, raise the loss allowance; if you want two coats, set the coats and the calculator doubles the kits.
Professional and bulk epoxies are specified by thickness instead. One US gallon spread 1 mil (0.001 in) thick covers 1,604 sq ft, so coverage per gallon is 1,604 × volume solids ÷ dry mils. A 100% solids epoxy has nothing to evaporate, so a 10 mil coat is 10 mils wet and 10 mils dry and covers about 160 sq ft per gallon. A 50% solids water-based epoxy loses half its thickness as it cures, so it must go on 20 mils wet to leave 10 dry — and covers only 80 sq ft per gallon at that build. The calculator shows the wet film so you can check it with a wet-film gauge.
Preparation, moisture and flakes
Epoxy fails at the bond far more often than in the film. The slab must be clean, free of oil and sealers, and profiled — the International Concrete Repair Institute describes surface profiles from CSP 1 (nearly flat) up; thin coatings typically want CSP 2–3, which feels like medium sandpaper and comes from acid etching or diamond grinding. Moisture coming up through the slab will push a coating off: tape a 2 × 2 ft plastic sheet down for at least 16 hours (the ASTM D4263 method), and if the concrete darkens or droplets form, use a moisture-tolerant primer or get the slab tested properly.
Decorative vinyl flakes hide imperfections and add grip. The amount varies enormously with the look: a light sprinkle like most DIY kits include is about 1 lb per 200 sq ft, while a full broadcast "to refusal" — throwing flakes until the wet coat can't take any more — is around 6–8 sq ft per lb of ¼ in flake, more for smaller flakes. Full broadcasts are scraped and vacuumed after curing and locked in with one or two clear topcoats, so budget for those coats too. Wear spiked shoes to walk on the wet coat, and keep cars off for the full cure time on the label.
Reference table
| Dry film per coat | 100% solids · 50% solids (sq ft/gal) |
|---|---|
| 3 mils | 535 · 267 |
| 5 mils | 321 · 160 |
| 8 mils | 200 · 100 |
| 10 mils | 160 · 80 |
| 15 mils | 107 · 53 |
Key facts
- 1 mil
- 0.001 in = 25.4 µm
- 1 gal at 1 mil
- covers 1,604 sq ft
- Full flake broadcast
- ≈ 6–8 sq ft per lb of ¼ in flake
- Moisture check
- taped plastic sheet test (ASTM D4263) for 16–24 h
Tips & common mistakes
- Diamond-grind or acid-etch to a rough "120-grit sandpaper" feel (CSP 2–3); epoxy on smooth, sealed concrete peels.
- Tape a 2 × 2 ft plastic sheet to the slab overnight: condensation underneath means moisture that needs a moisture-tolerant primer.
- Mix only what you can roll out within the pot life and pour it out onto the floor in a ribbon — left in the bucket it heats up and cures faster.
- Wait for the recommended temperature (often 55–90 °F) and keep cars off for the full cure time, often 5–7 days.
Frequently asked questions
How much epoxy do I need for a 2-car garage?
A 400–576 sq ft two-car garage needs two to three 250 sq ft DIY kits per coat (allowing 10% for porous concrete), or about 4.5–8 gallons of 100% solids epoxy for two coats at 8–10 mils.
How many square feet does a gallon of epoxy cover?
It depends on thickness and solids: 1,604 × solids ÷ mils. 100% solids epoxy at 10 mils covers 160 sq ft/gal; at 5 mils, 320. A 50% solids water-based epoxy covers half as much at the same dry film.
How thick should garage floor epoxy be?
DIY water-based kits go on thin — a few mils dry per coat, which is why they are rated at 250 sq ft or more per kit. Professional 100% solids systems are often 8–12 mils for the base and 3–8 mils for the topcoat, roughly 15–30 mils in total.
How many flakes do I need for an epoxy floor?
From about 1 lb per 200 sq ft for a light sprinkle to 1 lb per 6–8 sq ft for a full broadcast. A 400 sq ft garage takes about 2 lb lightly sprinkled or 50–65 lb for a full broadcast.
What does 100% solids epoxy mean?
Nothing evaporates as it cures, so the wet film equals the dry film. A 50% solids product loses half its thickness as water or solvent leaves, so it must go on twice as thick for the same result.
Sources
- Dampney – Calculating coating requirements — accessed : “such a paint applied to a film thickness of 1 mil (0.001 inch …) would be 1604 square feet … if a coating were 45% solids by volume, its theoretical coverage would be 1604 X 0.45 or 722 square feet at 1 mil dry film thickness”
- Trade Epoxy – how much flake for a full broadcast floor — general reference — not cited for a specific figure
- ASTM D4263 – indicating moisture in concrete by the plastic sheet method — general reference — not cited for a specific figure
- International Concrete Repair Institute – ICRI 310.2R concrete surface profiles — general reference — not cited for a specific figure
Default values (yields, coverage rates and densities) are typical figures from manufacturer literature. Always check the label on the product you buy.
Related calculators
- Paint CalculatorWork out gallons or liters for a room, including textured walls at 200–300 sq ft per gallon, plus doors, coats and tin sizes.
- Concrete Slab CalculatorEstimate cubic yards and bags for a slab or patio, including a 12×12 ft pad at 4 in, with waste, the formula and a shopping list.
- Square Footage CalculatorFind the area of a room or yard in square feet, square meters and square yards — rectangles, triangles, circles and trapezoids.
Learn more in our guides
Method, waste and worked examples: Paint coverage: coats, waste and tin sizes.
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DIYCalcLab. “Epoxy Floor Calculator.” Oct 19, 2026. https://diycalclab.com/paint/epoxy-floor-calculator/
Estimates only. Verify quantities with your supplier and local building codes. For structural, electrical or safety-critical work, consult a licensed professional. Full disclaimer.