Free tool

Square footage estimator

Enter room dimensions to get wall and ceiling area and the gallons you'll need — then price it in the cost calculator.

Wall area (gross)352 sq ft
Less openings− 51 sq ft
Net wall area301 sq ft
Ceiling area120 sq ft
Total paintable421 sq ft

Paint needed (2 coats)

3 gal

Price this job in the cost calculator

Openings are approximate (21 sq ft/door, 15 sq ft/window). Measure large openings for precision.

Questions

How do I calculate the square footage of a wall to paint?

Multiply the room's perimeter by the wall height: 2 × (length + width) × height. For a 12 × 10 room with 8-foot walls that's 2 × 22 × 8 = 352 square feet before subtracting doors and windows.

Should I subtract doors and windows?

For a tighter estimate, yes. This tool subtracts about 21 sq ft per door and 15 sq ft per window. On small jobs many painters skip it and paint the extra as buffer.

How much paint do I need for a room?

Divide the total paintable area by the paint's coverage (about 350 sq ft/gallon) and multiply by the number of coats. Most single rooms need 1–2 gallons for two coats of wall paint.

Start quoting in the next 10 minutes.

Set up your company, build your first paint-specific estimate, and send it for signature today. 30-day free trial — no credit card.