Paint Calculator
Enter your room dimensions and get an accurate estimate of how much paint you need — no guesswork, no waste.
Fill in your room details and click Calculate to see your paint estimate.
How to Calculate How Much Paint You Need
Getting the right amount of paint before heading to the store saves you time and money. Too little means a second trip; too much means wasted product sitting in your garage.
The Basic Formula
Add up the total wall area of the room (perimeter × ceiling height), subtract the area of doors and windows, then divide by the paint's coverage rate. Multiply by the number of coats you plan to apply.
Why Add a Buffer?
Paint coverage listed on the can assumes ideal conditions: smooth walls, one coat, no waste. Real-world painting always uses more. We recommend rounding up to the nearest gallon and keeping a quart in reserve for touch-ups.
Coverage by Paint Type
Standard latex paint covers around 350 square feet per gallon. Premium paints with higher solids content can cover up to 400 square feet. Rough or textured surfaces absorb more paint and may only yield 300 square feet per gallon.
Should You Paint the Ceiling?
This calculator covers walls only. For the ceiling, measure the floor area of the room and apply the same coverage formula separately. Ceiling paint typically uses a flat finish with slightly different coverage.