Paint Calculator

A gallon of paint typically covers 350–400 square feet per coat on smooth walls. Textured, rough, or porous surfaces absorb more paint and may only yield 200–300 sq ft per gallon.

Most rooms need 2 coats for even, opaque coverage. Use 1 coat for a fresh-color touch-up over the same color, and 3 coats when painting a dark color with a much lighter shade or a fresh primer.

Yes. Buy 10% more than calculated to account for roller nap absorption, brush waste, touch-ups, and potential mixing differences between cans. It is better to have a little left over than to run short.

Doors are approximately 20 sq ft (e.g., 6.7 x 3 ft) and windows are approximately 15 sq ft (e.g., 3 x 5 ft). Since these surfaces are not painted with wall paint, subtracting them gives a more accurate estimate.

No, this calculator covers only the four walls. For ceilings, calculate separately using Length x Width. Ceilings usually require 1–2 coats of a dedicated ceiling paint.

Standard ceiling height in US homes is 8 feet. Many newer homes have 9 or 10 foot ceilings. Higher ceilings increase wall area significantly — a 10 ft ceiling in a 12x10 room adds 44 more square feet of wall area versus an 8 ft ceiling.