The Paint for a House calculator estimates the number of gallons of exterior
paint needed to paint a house based on the length, width, height of the framing and roof.
INSTRUCTIONS: Choose units and enter the following:
- (L) Length of House
- (W) Width of House
- (H1) Height of Building
- (H2) Height of Frame
- (WD) Number of Windows
- (LWD) Number of Large Windows
- (DR) Number of Doors
- (CT) Number of Coats
Gallons of Exterior Paint for a House (GP): The calculator returns the estimate of exterior paint needed in gallons, and the approximate paint surface area in square feet. However, these can be automatically converted to compatible units via the pull-down menu.
The Math / Science
The calculator computes the surface area of the house exterior. It then divides the area by 300 square feet per gallon to compute the number of gallons of exterior paint. Most manufacturers call for one gallon of exterior paint to cover 300 square feet (ft2). The formula for the paintable surface area of a common gabled house is:
`A = (2*L* H2 + 2*W*H2 + W * (H1-H2) ) - (WD*15 ft^2 + DR * 21 ft^2 + LWD * 30 ft^2)`
where:
- A = Paintable Surface Area of House
- L = Length of House
- W = Width of House
- H1 = Height of Building
- H2 = Height of Framing
- WD = Number of Windows (~ 15 ft2 per window)
- LWD = Number of Large Windows (~ 30 ft2 per large window)
- DR = Number of Doors (~ 21 ft2 per door)
Paint Calculators:
- Paint for a Room: computes the number of gallons of paint or primer needed to paint an entire room, the four walls and ceiling and just the walls.
- Paint for a Wall: computes the number of gallons of paint or primer needed to paint a wall or any rectangular area (wall or ceiling).
- Exterior Paint for a House: computes the number of gallons of exterior paint for a gabled building like a common house.
- Cost to Paint or Primer a Room: (CLICK HERE)
- Cost to Paint a Wall: (CLICK HERE)
- Cost to paint or prime a ceiling: CLICK HERE
- Paint Pricing Survey
Paint Pricing Survey Data
One should use the pricing for paint or primer that can be bought locally since prices may vary. However, the following prices are recent U.S. dollar costs for one gallon of paint or primer in the United States:
- Paint Pricing Survey date: 7/29/22
- Paint Price Survey Source (online): HomeDepot
- Price of premium (high quality) paint: $61.94 USD
- Price of medium grade paint: $48.98 USD
- Price of economy paint: $26.98 USD
- Price of primer: $19.98 USD