Painting
walls · rooms · trimWall Paint
Paint coverage based on wall dimensions, minus doors and windows, plus number of coats and coverage rate.
Quick Room Estimator
Ballpark paint gallons for a rectangular room without measuring individual walls, using room length, width, and height.
Trim & Baseboards
Paint needed for trim, baseboard, or casing runs, sized by linear footage and trim width, in quarts.
Planning a Painting Project
Paint estimates come down to surface area and coverage rate — how many square feet you're covering, divided by how far a gallon of your specific paint actually goes. The three calculators here cover the most common residential painting scenarios: precise wall estimates, fast room ballparks, and trim work.
How These Calculators Work Together
Use the Wall Paint calculator when you know your exact door and window count for the most accurate gallon estimate. Use the Quick Room Estimator when you just want a fast ballpark without measuring every opening. Use the Trim & Baseboard calculator separately for casing, baseboards, and trim, since those are usually painted with a different product (often a more durable enamel) in smaller quantities measured in quarts, not gallons.
Frequently Asked Questions
Why do these calculators give different answers for the same room?
The Wall Paint calculator subtracts real door and window area, while the Quick Room Estimator doesn't — so the Quick Room Estimator will always estimate slightly more paint than the Wall Paint calculator for the same room. Use the Quick Room Estimator for speed, and the Wall Paint calculator when you want a tighter number.
What paint coverage rate should I use?
350 sq ft per gallon is a common average, but coverage varies by paint brand, sheen, and surface texture — always check the coverage rate printed on your specific paint can rather than relying on a generic average for a large order.