Enough paint. Less guesswork.
Estimate the paint needed for a rectangular room's walls. Adjust the number of coats, openings, product coverage and waste allowance.
Your wall measurements
Measurements are in feet. We subtract the combined door and window area from four walls.
344 sq ft of wall after openings · 2.16 gallons calculated, before rounding up.
How the estimate works
Wall area = 2 × (length + width) × height. Subtract doors and windows. Multiply by number of coats and (1 + waste percent ÷ 100), then divide by your product's stated square feet per gallon. Finally, round up to full gallons for a simple purchase estimate.
Not included: ceiling, trim, sloped or irregular walls, textured surfaces, primer, surface porosity or different paint pack sizes. The product label and actual surface preparation determine final requirements.