Paint Calculator
⚙️ Input Values
📊 Result
📋 Calculation History
📖 About the Paint Calculator
Estimating paint correctly saves you time, money, and return trips to the hardware store. The standard coverage for most interior latex paint is 350–400 square feet per gallon (32–37 m² per liter). However, porous surfaces like bare drywall or textured walls may require more.
To calculate paint needed: measure the perimeter of the room, multiply by the ceiling height to get total wall area, then subtract roughly 20 sq ft (1.86 m²) for each door and 15 sq ft (1.4 m²) for each standard window. Divide by coverage rate, then multiply by number of coats.
Dark colors covering light paint, or vice versa, often need 2–3 coats. Primer is recommended for new drywall, major color changes, or stain coverage. Our paint calculator accounts for all these variables and gives you a gallon count with a 10% buffer built in.