Paint Coverage Calculator Guide

Estimate gallons of paint by combining paintable area, number of coats, and the coverage rate for the product you plan to use.

Use the paint calculator

The ATHENA Paint Calculator calculates paintable wall area from room dimensions and subtracts approximate door and window area. You can add the ceiling, choose the number of coats, and enter the product's coverage per gallon.

Paint coverage formula

Paint needed = paintable area × coats ÷ coverage per gallon

Example

If you have 700 square feet of paintable area, plan for two coats, and the product states 350 square feet of coverage per gallon, the calculation is 700 × 2 ÷ 350 = 4 gallons before any planning allowance.

Why coverage matters

Paint products vary. Surface texture, porosity, color changes, application method, and the product itself can change how much paint is actually used.

Use the product label when available

ATHENA starts with a 350 square-foot-per-gallon planning value, but you can replace it with the coverage printed on the exact paint product you plan to use.

Ready to calculate?

Run your room numbers here: Free Paint Calculator.

How Much Paint Do I Need? · Paint Coverage Per Gallon Guide

Compare interior wall paint on Amazon (paid link)

As an Amazon Associate I earn from qualifying purchases.