How to Estimate Interior Paint for a Whole House

Repainting an entire house is a major project. One of the biggest mistakes homeowners make is underestimating the amount of paint required. Running out of paint mid-project is a nightmare because a second batch might have a slightly different tint (dye lot).

Here is how to estimate paint for an average US home, room by room.

The Average Math

A typical 2,000 square foot home usually requires 10 to 15 gallons of wall paint for two coats. However, a house with high ceilings and lots of open space will need more.

Room-by-Room Estimates

Assuming 8-foot ceilings and standard room sizes:

Standard Bedroom (10x12 ft): 2 gallons for walls, 1 gallon for ceiling.
Master Bedroom (12x16 ft): 2.5 gallons for walls, 1 gallon for ceiling.
Living Room (15x20 ft): 3 gallons for walls, 1.5 gallons for ceiling.
Bathroom (5x8 ft): 1 gallon for walls (often only half is painted due to tile), 0.5 gallon for ceiling.
Kitchen: 2 gallons for walls (many walls are covered by cabinets).

Don't Forget the Trim

Baseboards, crown molding, window frames, and interior doors all need semi-gloss paint. For an entire house, you can easily go through 1 to 2 gallons of trim paint, even though the square footage seems small.

5 Steps to Get the Exact Number

Measure total wall area: Multiply the total perimeter of all rooms by the ceiling height.
Subtract doors and windows: Deduct 20 sq ft per door and 15 sq ft per window.
Subtract cabinets: In kitchens and bathrooms, subtract the area covered by cabinetry.
Divide by 350: This gives you the number of gallons for one coat.
Multiply by 2: Always buy enough for two coats. It provides a much better finish and durability.

Pro Tips to Save Money

Buy a 5-gallon bucket instead of individual gallons if you are painting multiple rooms the same color. It is significantly cheaper per gallon and ensures consistent color.
Use a high-quality brush and roller. Cheap tools soak up too much paint.
Wrap your rollers in plastic wrap between coats instead of washing them.

Before heading to Home Depot, use our Paint Calculator to double-check your measurements. It will give you a precise gallon count so you can buy everything you need in one trip.