Epoxy Garage Floor Calculator
Epoxy is bought by coverage, and every coat uses another full round of coverage over the same floor — so a two-coat garage needs twice the floor area in coverage. Enter your floor and get gallons, flake, and kit counts. Runs 100% in your browser.
Epoxy Garage Floor Calculator
About this epoxy garage floor calculator
Epoxy quantity is floor area × coats × (1 + waste), divided by coverage per gallon, rounded up — and the coats multiplier is the part people miss. A 20 × 20 ft two-car garage is 400 sq ft, but two coats need 800 sq ft of coverage before waste, not 400. Coverage per gallon is product-specific and thickness-specific: 100%-solids epoxy at a pro-grade 10 mils covers about 160 sq ft per gallon, while a water-based DIY product at thin build covers roughly 260 — always use the coverage printed on your product, not a generic figure. Our epoxy guide covers systems, prep, and the kit math.
Two coats is the standard build: the first coat seals the slab, the second carries the wear layer. One coat wears quickly under cars; three coats suit heavy builds and metallic floors. Rough, porous, or heavily stained concrete drinks more on the first coat — use the 15% waste figure there, and patch cracks and prime bare concrete first so the epoxy does not soak in unevenly.
Flake is the decorative broadcast thrown into the wet base coat: a light accent uses about 2 lb per 100 sq ft, a full broadcast (where the base coat disappears entirely) about 5 lb per 100 sq ft. A 400 sq ft garage at full broadcast needs about 20 lb of flake. Kits bundle this differently — a typical 500 sq ft kit covers a 250 sq ft floor twice — so if your product is sold as a kit, enter the kit's per-coat coverage in the coverage field and read the result as kits.
How to use
- Measure your garage length and width in feet, wall to wall at the widest points.
- Choose coats — 2 is standard — and enter your product's coverage per gallon from the label.
- Pick a waste allowance and your flake level (none, light accent, or full broadcast).
- Optionally enter the price per gallon, then press Calculate.
Good to know
- Coverage per gallon varies by product and target thickness — the label figure governs; this calculator cannot know your product's solids content or mil build.
- Does not include primer, crack filler, topcoat, or prep materials (grinder rental, degreaser, acid etch) — budget those separately.
- Moisture matters: concrete that fails a moisture test (ASTM F1869/F2170/D4263) needs a vapor-barrier primer first, or the coating can delaminate.
Frequently asked questions
How much epoxy do I need for a 2-car garage?
A 20 × 20 ft (400 sq ft) garage at 2 coats and 200 sq ft per gallon needs 800 sq ft of coverage — 5 gallons with a 10% waste allowance. A 500 sq ft kit covers the same garage twice over two kits.
How many square feet does a gallon of epoxy cover?
It depends on solids and thickness: 100%-solids epoxy at 10 mils covers about 160 sq ft per gallon; water-based DIY products at thin build cover roughly 260. Use your product's label figure.
How many coats of epoxy should a garage floor get?
Two coats is standard — a sealing base coat plus a wear coat. One coat wears quickly under cars; three coats suit heavy builds and metallic floors.
How much flake do I need for a garage floor?
A light accent uses about 2 lb per 100 sq ft; a full broadcast uses about 5 lb per 100 sq ft — about 20 lb for a 400 sq ft garage at full broadcast.
Can I use this calculator for epoxy kits instead of gallons?
Yes — enter the kit's coverage per coat in the coverage field and read the gallon figure as kits. A 500 sq ft kit coats a 250 sq ft floor twice.