Paint Coverage & Coats Calculator

How to calculate paint coverage?

To determine the amount of paint required for your project, you first need to calculate the net surface area of the walls. This net area is then multiplied by the number of coats you plan to apply and finally divided by the spread rate of the paint to determine the total gallons needed.

Gallons = ((Wall Area - Openings) × Coats) / Spread Rate

Using the Paint Coverage calculator: an example

For a 500 sq ft room with 1 door and 2 coats.

Step-by-step calculation:

1. Subtract 20 sq ft per door and 15 sq ft per window
2. Multiply remaining area by 2 coats
3. Divide by 350 sq ft/gallon coverage

Frequently Asked Questions

How much area does one gallon of paint cover?

Most standard paints cover between 350 and 400 square feet per gallon on smooth surfaces.

Should I always calculate for two coats?

Yes, most professional finishes require at least two coats for uniform color and durability.

What about ceiling paint?

Ceilings are calculated the same way; just measure the floor area to get the ceiling square footage.