How many square feet does a gallon of paint cover?

One gallon of paint typically covers 350-400 square feet with one coat on smooth, non-porous surfaces. Rough or textured surfaces may only get 250-300 square feet per gallon. Always check the manufacturer's coverage specifications on the can.

Should I subtract area for doors and windows?

Yes, subtract door areas (about 20 sq ft each) and window areas from your total wall space. However, many professionals keep these measurements in the calculation to account for extra paint needed for multiple coats and touch-ups.

How many coats of paint do I need?

Most projects require 2 coats for proper coverage and durability. Dark colors over light walls, or light colors over dark walls may need 3 coats. Primer is recommended before painting new drywall or when making dramatic color changes.

Do I need different amounts for walls versus ceilings?

Ceilings often need the same or slightly more paint than walls because the surface may be more porous. Use flat paint for ceilings and eggshell or satin for walls in most cases, which affects coverage slightly.

Everyday

Paint Calculator

Estimate how much paint you need for your room based on dimensions and openings.

Room Dimensions

Length (ft)

Width (ft)

Height (ft)

Deductions & Details

Doors

Windows

Coats

Coverage (sq ft/gal)

Enter dimensions to see results

How to Use This Calculator

Measure Wall and Ceiling Dimensions

Measure the length and height of each wall you plan to paint. For ceilings, measure length and width. Record all measurements in feet.

Enter Room Details

Input wall dimensions, ceiling area, and subtract door/window areas. Specify the number of coats you plan to apply (typically 2 coats for best results).

Review Paint Quantity

The calculator shows how many gallons needed based on standard coverage rates (typically 350 sq ft per gallon). Round up to the nearest gallon when purchasing.