EpoxyGrindTool
Epoxy Coverage Calculator: How Much Epoxy Do You Need?
Enter your floor size and coating system below to estimate gallons needed, then jump straight to kits sized for that coverage.
Every epoxy, polyaspartic, and metallic system spreads differently depending on its volume solids (how much of the wet material stays behind as cured film) and how thick you apply it (target mil thickness, or DFT — dry film thickness). This calculator uses the standard coatings-industry spreading-rate constant to turn those two numbers, plus your square footage and coat count, into a gallons estimate.
The defaults below are typical figures for each system — not a spec for any specific product. Always check the technical data sheet (TDS) on the actual kit you're buying and adjust the solids % and mil thickness fields to match; coverage claims vary by brand, and the manufacturer's number for their own product is always the more accurate one.
Includes a standard 10% loss factor for roller/tray waste and surface absorption. Solids % and mil thickness default to typical figures per system — always confirm against your specific product's technical data sheet before buying.
How the math works
The formula: coverage (sq ft per gallon) = 1604 × volume solids ÷ target mils. The constant 1604 comes from the physical relationship between a gallon's volume and a 1-mil-thick film — spread one gallon of a 100%-solids material at exactly 1 mil thick and it covers 1,604 sq ft. Lower the solids content or raise the target thickness and that number drops.
From there: gallons per coat = floor area ÷ coverage-per-gallon, then multiplied by a 10% loss factor to account for what stays in the roller nap, the mixing bucket, and porous concrete that drinks more than a smooth sealed floor. Multiply by your number of coats for the total.
This is a planning estimate for buying the right amount of material, not a substitute for the coverage rate printed on your actual kit — see our complete garage floor epoxy guide for how coats fit into the full job.
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FAQ
Why does the calculator ask for volume solids instead of just letting me pick a product?
Volume solids and recommended mil thickness are specific to each manufacturer's formulation. Using system-level defaults gets you in the right ballpark for planning, but the number on your actual kit's technical data sheet will always be more accurate than a general industry figure.
What is DFT and why does it matter more than how much I roll on?
DFT (dry film thickness) is how thick the cured coating ends up, in mils — not how much wet material you spread. A thin film wears through fast regardless of how carefully you rolled it on; hitting the target DFT is what actually determines durability.
Why is the default solids % lower for polyaspartic than epoxy?
Many polyaspartic formulations run slightly below 100% volume solids, commonly in the 80-95% range depending on the product, versus most garage-grade epoxy kits which are formulated at or near 100% solids. Check your specific product's TDS — some polyaspartic systems are also sold at 100% solids.
Should I buy exactly what the calculator says?
No — round up to the next full unit the kit is sold in, and buy a little extra rather than stretching a kit thin. Running short mid-coat on a two-part product you've already mixed is a much bigger problem than having a partial container left over.
Does this calculator account for flake broadcast or a clear topcoat separately?
No — run the calculator once per coat type (e.g., once for your pigmented base coat, once for a clear topcoat) since they often have different target mil thicknesses, and add the results together for your total shopping list.