Paint Calculator

Estimate how many gallons of paint you need for your room.

Room Dimensions

Deductions

Standard door: 21 sq ft. Standard window: 12 sq ft.

Paint Settings

Paint Required

0
Gallons
Total Area 0 sq ft
Paintable Area 0 sq ft
Tip: Standard coverage is approx 350-400 sq ft per gallon. Primer typically covers less (200-300 sq ft).

How to Calculate How Much Paint You Need

Calculating the right amount of paint saves money and reduces waste. One gallon of paint typically covers about 350 square feet.

The Calculation Steps

  1. Calculate Total Wall Area: Add the length of all walls together and multiply by the height. (Perimeter × Height).
  2. Subtract Doors & Windows: Subtract the area of doors (approx 21 sq ft) and windows (approx 12 sq ft).
  3. Divide by Coverage: Divide the net square footage by the coverage rate of your paint (usually 350 sq ft/gal).
  4. Multiply by Coats: Multiply the result by the number of coats you plan to apply.

This calculator automatically handles the math for you, ensuring you buy the right amount for your project.