Estimate total paint gallons required to cover wall areas.
Calculator Parameters
Enter details and click calculate to view the results instantly.
Calculation Examples
Scenario Inputs
Output Result
length : 40, height : 8, coats : 2
Area: 640 Sq.Ft, Required: ~ 2 Gallons
About Paint Calculator
Wall Paint Area & Gallons Calculator. Estimate total paint gallons required to cover wall areas. Starlightopia provides this tool completely free and online, optimized for instant, accurate computations.
How It's Calculated
How do you calculate the wall surface area of a room?
Surface Area = Total Wall Perimeter Length x Wall Height.
Technical Specifications
CategoryConstruction
Target ValuePaint Required
Inputs Required (3)
Total Walls Perimeter Length (Feet) (number)
Wall Height (Feet) (number)
Number of Coats (number)
Frequently Asked Questions
How many square feet does one gallon of paint typically cover?
One standard gallon of paint covers between 350 and 400 square feet of wall area.
How do you calculate the wall surface area of a room?
Surface Area = Total Wall Perimeter Length x Wall Height.
Should I factor doors and windows out of the paint calculation?
For precise estimates, you can subtract 20 square feet for each standard door and 15 square feet for each average window.
Why do raw, unpainted drywall surfaces require extra primer paint?
Unfinished drywall is highly porous and absorbs paint quickly, so priming first prevents uneven textures and reduces the coats needed.
Are two coats of paint always necessary when remodeling?
Two coats are generally recommended to ensure uniform color depth and hide the old paint coat beneath.