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Paint Calculator

How many gallons of paint do you need? Enter your room dimensions and we'll figure it out.

Room Dimensions

Room Length (ft)

Room Width (ft)

Ceiling Height (ft)

Deductions

Number of Doors

Number of Windows

Options

Coats of Paint

Paint Coverage (sq ft/gal)

Include ceiling

Paint Needed (Walls)

—

Wall Area

—

sq ft

Net Paint Area

—

after doors & windows

Ceiling Area

—

sq ft

Total Gallons

—

walls + ceiling

How paint coverage works

Standard paint covers about 350–400 sq ft per gallon on smooth surfaces. Dark colors, rough textures, or priming over raw drywall may require 300 sq ft per gallon or an extra coat.

Wall area = 2 × (Length + Width) × Height
Net area = Wall area − (Doors × 20 sq ft) − (Windows × 15 sq ft)
Gallons = (Net area × Coats) ÷ Coverage per gallon

Always buy 10% extra for touch-ups. Store leftover paint in an airtight container for 2–5 years.