Home & DIY · FREE CALCULATOR

Wall Paint Calculator

Estimate gallons and purchase cost for painting four rectangular room walls. Change the sample numbers to get an instant estimate tailored to your situation.

Your inputs

Adjust any value to update the results.

Calculated results

Based on your current inputs

Calculating…

UNDERSTAND THE MATH

How this calculator works

Provide room dimensions, the combined area of doors and windows, your chosen coats, and the paint coverage on the product label.

Formula

(2 × (length + width) × height − openings) × number of coats ÷ coverage per gallon × allowance.

Before you use the result

Calculator outputs are estimates based on the numbers you provide. Replace the examples with measurements, costs, rates, or product information appropriate to your situation.

Keep in mind

Ceilings and trim are excluded. Texture, porosity, primer, and application method can change real coverage.