Paint Calculator: How Many Gallons for Your Room?

🔗 Open the full-page Paint Calculator

Plan purchases before you shop

Running out of paint mid-job—or overbuying several gallons—is expensive and frustrating. This calculator uses your room’s footprint, wall height, optional deductions for openings, and the number of coats to estimate how many gallons to purchase.

How to use it

1. Measure length and width of the floor (feet).
2. Enter wall height (feet).
3. Add doors and windows as total square feet to subtract (rough estimate is fine).
4. Set coats (primer counts toward coverage planning if you use a separate primer product).

Coverage note

The tool assumes a typical ~350 square feet per gallon per coat for many interior latex paints. Textured drywall, deep colors, or porous surfaces may need more product; your paint can label is the final authority.