Exterior Paint Calculator
Exterior surfaces are often more porous or textured, so coverage is reduced versus smooth drywall.
Step 1: Units
Step 2
Enter project measurements
Use decimals if needed (e.g. 3.5).
Step 3
How to use this calculator
Enter the surface area and number of coats. Adjust coverage if your product label differs.
What the math is doing
Gallons = (square feet ÷ coverage per gallon) × coats. Liters use the same ratio after unit conversion.
How to measure
Multiply wall lengths by height and subtract large openings. Ceilings use floor footprint area.
Frequently asked questions
Why does coverage differ?
Texture, porosity, color change, and application method all change spread rates.
Primer vs paint?
Primers often list different coverage; use the primer calculator for primer coats.
Spray vs roll?
Spray can change overspray losses; add waste percentage.
Sheen impact?
Sheen changes appearance more than coverage math; still verify label rates.