🎨 Paint Calculator

How Much Paint Do You Actually Need?

This calculator multiplies your total wall width by wall height to get the gross wall area, subtracts space for doors and windows, multiplies by the number of coats you plan to apply, then divides by your paint's coverage rate per gallon to estimate how many gallons to buy.

Typical Paint Coverage

Most standard interior wall paints cover approximately 350-400 square feet per gallon on a smooth, primed wall — though rougher or more porous surfaces, and darker color changes, may require more paint or an extra coat.

Tips for Estimating Accurately

• Measure each wall's width individually and add them together for the total width, rather than guessing room perimeter
• Two coats is standard for most interior painting projects, especially over a different existing color
• Round your final gallon estimate up — it's much easier to have a little leftover paint than to run out mid-project and risk a color-batch mismatch
• Primer is calculated and purchased separately from top-coat paint

❓ Frequently Asked Questions