Understanding the Paint Calculator
A paint calculator tells you how many gallons or liters you need to cover a room or surface, based on its area and the number of coats. It prevents the frustration of running out halfway through a wall or being left with cans of unused paint.
Coverage and coats
A gallon of paint typically covers around 350–400 square feet in a single coat. The calculator divides your total surface area by this coverage and multiplies by the number of coats. Most jobs need two coats for an even, durable finish, and dark or drastic color changes may need more.
Surface and subtractions
Porous or textured surfaces drink up more paint than smooth ones, and bare drywall may need a primer coat first. You can subtract large openings like windows and doors from the area, but many painters skip this for a small built-in buffer. Buying all your paint at once ensures a consistent color batch.
Tips & things to know
- •Plan for two coats on most walls.
- •Primer is worth it over bare or patched surfaces.
- •Buy all paint in one batch for consistent color.