Construction
Paint Calculator
Stop buying too much (or running out mid-wall). Enter your room dimensions, subtract doors and windows, pick your coats — done.
Enter the wall total and ceiling height to start.
Rules of thumb
- Standard door = 21 sq ft. Standard window = 15 sq ft.
- Most quality interior paints cover 350 sq ft / gallon. Cheap paint, rough walls, or porous surfaces drop this fast.
- Always plan 2 coats for a fresh look. Color changes need 3.
- Buy a little extra — touch-ups years later are easier if the can matches.
FAQ
What's 'wall length total'? +
Add up the length of every wall in the room. For a 12 × 15 ft room: (12+15) × 2 = 54 ft.
Does this include the ceiling? +
No — this calculator is for walls only. Ceiling coverage = length × width. Add it separately if you're painting it.
Why round up? +
Paint comes in fixed sizes (gallons, quarts). Running out mid-wall means a color-match nightmare. Round up.