Enter the room, the doors and windows, and the coats you plan. You get the gallons to buy and the walls you are actually covering.
How it works
Perimeter × height gives wall area. Subtract 21 sq ft per door and 15 sq ft per window, multiply by coats, then divide by coverage per gallon.
Before you order
- Buy the same batch or box your gallons together so the color stays even across the room.
- Two coats of a color change is normal; a same-color refresh can sometimes get by with one.
- Save a labeled jar of leftovers for touch-ups.
Common questions
How much does a gallon of paint cover?
About 350 to 400 sq ft on a smooth, primed wall. Textured walls and strong color changes cover less, so lower the coverage input if yours is rough.
Should I subtract doors and windows?
Yes for rooms with several openings. In a small room with one door, the difference may not change how many gallons you buy.