Paint Coverage Calculator

What the Paint Coverage Calculator does

Paint is bought by the gallon or litre, and each can covers a stated area per coat. Work out the wall area, subtract doors and windows, add the ceiling if you are painting it, multiply by the number of coats and divide by the coverage. Rough or porous surfaces need more.

It also works as a interior paint estimator or a how much paint do I need calculator.

Formula

• Wall area = perimeter × height − doors × 20 sq ft − windows × 15 sq ft
• Gallons = (wall area + ceiling) × coats ÷ coverage per gallon

Worked example

Using the starting values in the calculator above:

How to read the result

New drywall, strong colour changes and textured walls often need a primer coat and lower coverage than the label states.

Buying all the paint in one batch avoids slight colour differences between cans.

Quantities are estimates. Check product data sheets and local codes, and confirm with your supplier before ordering.

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Browse every calculator in Construction and Materials Calculators, or talk to us about websites for construction and trades businesses.