DATUM

Paint Coverage Calculator

Wall area minus openings, times the number of coats, rounded up to whole cans — and how much is left for touch-ups.

Paint Coverage Calculator

Wall area minus the openings, times the number of coats, rounded up to whole cans — and it tells you how much you will have left for touch-ups, which is the point of buying paint.

Gross wall area
Deductions
Net area to paint
Area × coats
Paint required
Cans to buy
Left over

Deductions use 21 ft² per door and 15 ft² per window — ordinary US sizes (about 3×7 and 3×5). Coverage varies by product and by what you are painting over: the figure on the can assumes a smooth, sealed, primed surface. Bare drywall, skim coat, textured plaster and masonry all drink more, sometimes half again. Take the number from the can you are actually buying and adjust it down for porous substrates rather than trusting the default here.