Buying too little paint means a second trip to the store; buying too much wastes money. This calculator estimates the gallons you need based on wall area and number of coats.
How to Use This Calculator
Enter the total wall area in square feet (add up all the walls you’re painting) and the number of coats you plan to apply, then click Calculate.
Formula
Gallons = (Area × Coats) ÷ 350, based on the common coverage estimate of about 350 square feet per gallon for a standard latex paint.
Frequently Asked Questions
How much wall area does one gallon of paint cover?
Typically around 350-400 square feet per coat, though this varies by paint brand, surface texture, and color change.
Do I need 2 coats every time?
Two coats is standard for most interior painting, especially with a color change. A single coat may suffice for touch-ups or same-color repaints.
Should I subtract doors and windows from wall area?
For a precise estimate, yes — subtract door and window area. For a simpler estimate, most people skip this and treat it as a small buffer.