Paint Calculator

Calculate exactly how many gallons of paint you need for any room or surface. Enter square footage and number of coats to get your estimate.

Results are estimates only — actual material needs vary by site conditions, waste, and product specifications. Always verify quantities with a qualified contractor before purchasing. HandymanCalc is not liable for material shortfalls or overages.

Surface Area
sq ft
ft²/gal
FAQ

Frequently Asked Questions

3 questions
Q1 How much does one gallon of paint cover?
One gallon of paint typically covers 350–400 square feet with one coat on a smooth surface. Rough or porous surfaces may require more paint.
Q2 Do I need a primer coat?
Primer is recommended when painting over bare drywall, dark colors, or stained surfaces. Add one coat of primer before your finish coats.
Q3 How do I calculate square footage for a room?
Multiply wall height by the perimeter of the room. Subtract approximately 20 sq ft per door and 15 sq ft per window.