Paint Calculator
Find out how many gallons of paint you need.
Room Dimensions
Openings to Subtract
Paint Details
Frequently Asked Questions
How much wall area does a gallon of paint cover? +
Most interior latex paints cover about 350-400 square feet per gallon on smooth surfaces. Rough or textured walls, bare drywall, and dark-to-light color changes will reduce coverage. This calculator defaults to 350 sq ft/gallon for a conservative estimate.
How many coats of paint do I need? +
Two coats are standard for most paint jobs. You may need three coats when painting over a dark color with a light one, or when using a paint with low opacity. A single coat can work for touch-ups or when using a paint-and-primer combo over a similar color.
What standard sizes does this calculator use for doors and windows? +
A standard door is calculated at 21 square feet (3 ft x 7 ft) and a standard window at 12 square feet (3 ft x 4 ft). These are typical US residential sizes. If your doors or windows differ significantly, adjust the count accordingly.
Should I subtract closet openings and other gaps from the wall area? +
For a quick estimate, subtracting doors and windows is usually sufficient. Most painters do not subtract small gaps like electrical outlets or vents since the extra paint accounts for waste and touch-ups.