How Much Paint Do I Need for a Garage?
Quick answer: add the four walls minus the garage door, then divide by 350–400 sq ft per gallon. A typical 20×20 two-car garage needs about 3 gallons per coat — 6 gallons for two coats, plus 1 gallon for the ceiling.
- The garage formula
- Subtract the big openings
- Wall vs floor paint
- Worked example: 20×20 two-car garage
- Ceiling and floor options
- FAQ
The garage formula
Garage walls follow the room formula: (length + width) × 2 × height. A 20×20 garage with 8 ft walls = 40 × 2 × 8 = 640 sq ft. Then subtract the garage door and the door into the house — garages have big openings that you shouldn't paint.
Subtract the big openings
A standard two-car garage door is about 16×7 ft = 110 sq ft; a single-car door is ~9×7 = 63 sq ft. Subtract the door, the door into the house (~21 sq ft) and any windows. In the 20×20 example that drops 640 → about 500–530 sq ft of paintable wall.
Wall vs floor paint
Use latex wall paint in satin or eggshell on garage walls — washable, dries fast, covers drywall. Semi-gloss near workbenches resists scuffs. The floor needs epoxy or concrete floor paint, not wall paint: wall paint flakes off concrete under car tires and foot traffic. Epoxy kits are sized in square feet and cover 150–300 sq ft per gallon per coat.
Worked example: a 20×20 two-car garage
- Walls = 40 × 2 × 8 = 640 sq ft
- Minus 2-car door (110) + house door (21) = 509 sq ft
- ÷ 350 sq ft/gal = 1.5 → buy 2 gallons per coat
- Two coats → 4 gallons for walls; ceiling +1 gallon
- Floor (400 sq ft) → 2–3 gallons of epoxy or floor paint
Ceiling and floor options
Painting the ceiling makes the garage feel finished and much brighter — in an 8 ft garage with exposed joists, flat white ceiling paint adds about 1 gallon per coat for a 20×20 footprint. For the floor, a two-part epoxy kit gives the most durable finish; acrylic floor paint is the budget option and needs recoating every couple of years.
FAQ
Add the four wall areas (length + width × 2 × height), subtract the garage door (about 110 sq ft for a 2-car), and divide by 350–400 sq ft per gallon. A typical 20×20 garage needs about 3 gallons per coat, or 6 gallons for two coats.
About 3 gallons per coat for a 20×20 two-car garage with 8 ft walls. The walls total 640 sq ft; subtract the 16×7 door (~110 sq ft) and the house door for about 510 sq ft — buy 3 gallons to cover cutting in.
Use latex wall paint in a satin or eggshell sheen — washable and dries fast. Semi-gloss stands up better near workbenches. For the floor, use epoxy or concrete floor paint, not wall paint.
Yes — painting the ceiling makes a garage feel finished and brighter. In an 8 ft garage, paint it flat white; it adds roughly 400 sq ft (20×20) to your total, or about 1 gallon per coat.
A 2-car garage floor (20×20 = 400 sq ft) needs about 2–3 gallons of epoxy or floor paint for one coat — floor paint covers 150–300 sq ft per gallon. Plan two coats for best durability.