Paint Calculator

Calculate wall area: 2 × (length + width) × height. Subtract doors (about 20 sq ft each) and windows (about 15 sq ft each). Divide by paint coverage (350-400 sq ft per gallon). A 12×15 ft room with 8 ft ceilings needs about 1.5 gallons per coat.

One gallon typically covers 350-400 square feet on smooth surfaces. Textured walls reduce coverage to 300-350 sq ft. Primer coverage is about 200-300 sq ft per gallon. The calculator adjusts for surface texture.

Most color changes need 2 coats for even coverage. Dramatic color changes (dark to light or vice versa) may need 3 coats. A primer can reduce the number of topcoats needed. The calculator accounts for multiple coats.

Yes, subtract them from total wall area. Standard door: 20 sq ft, standard window: 15 sq ft. If you're painting trim, add that area separately. The calculator has fields for doors and windows.

Flat paint hides imperfections but is less durable. Eggshell has slight sheen and is easier to clean. Semi-gloss is durable and moisture-resistant, ideal for kitchens and bathrooms. Coverage is similar for all sheens.

Multiply length × width for ceiling area. Ceilings typically need flat/matte paint with similar coverage to walls (350-400 sq ft/gallon). Add 10% extra for roller texture and absorption on textured ceilings.