How this calculator works
Most water-based epoxy floor paints cover 200–250 square feet per gallon on properly etched concrete. The calculator uses 250 sq ft per gallon as a typical rate, adds 10% for roll-off and edges, and multiplies by your number of coats.
400 sq ft × 1.10 × 2 ÷ 250 = 3.52 → 4 gallons.
Prep is everything
Etching or diamond-grinding the concrete surface is critical — un-prepped concrete causes epoxy to peel. Acid etching opens the pores so the epoxy bonds. Fill cracks and oil stains with an appropriate primer before the first coat.
Frequently asked questions
How many gallons of epoxy do I need for a 2-car garage?
A typical 2-car garage floor is 400–500 sq ft. For 2 coats, plan on 4–5 gallons (one 2-gallon kit per coat, plus a spare quart for edges).
How many square feet does a gallon of floor epoxy cover?
Most products cover 200–250 square feet per gallon on properly prepared concrete. Rough, porous, or first-coat application consumes more — use the lower end for planning.