Paint Calculator

Calculate how much paint you need for any room. Enter room dimensions, number of doors and windows, and coats to get the exact gallons needed.

Room Dimensions

Openings & Coats

Optional Settings

Frequently Asked Questions

How much paint do I need for a 12x12 room?
A 12x12 room with 8-foot ceilings has about 384 sq ft of wall area. After subtracting a door and two windows, you need roughly 2 gallons for two coats at standard coverage of 350 sq ft per gallon.
How many square feet does one gallon of paint cover?
One gallon of paint typically covers about 350 to 400 square feet with one coat. Coverage varies by paint type, surface texture, and application method.
Should I include the ceiling when calculating paint?
Include the ceiling if you plan to paint it. Ceilings often use a different paint finish, so you may want to calculate wall and ceiling paint separately.
How do doors and windows affect the paint calculation?
A standard door opening is about 21 square feet and a standard window is about 15 square feet. These areas are subtracted from the total wall area since they do not need paint.
Is this paint calculator free to use?
Yes. This calculator runs entirely in your browser with no signup, no ads tracking, and no data sent to any server.