How to Know How Much Paint to Buy

After you choose a paint scheme for your exterior or interior home painting project, you must determine how much paint you need to buy. Fortunately, you don’t have to worry about the math because you can find a paint calculator online. However, you do need to consider a number of variables including painting techniques and overall surface condition. With accurate measurements and precise calculations, you will ensure that you will have enough paint to complete the project. With proper planning, you can make accurate paint calculations and avoid any shortage and overage issues.

Paint Coverage Area

You can buy paint in one quart, one gallon or five gallon containers. Before purchasing paint, consider questions like: How much paint do I need to paint my house? How much paint do I need for one wall? And, how much area does a five gallon bucket of paint cover?

Check the paint container to determine the estimated coverage. Generally, a quart of paint covers about 100 square feet, and a gallon of paint covers 400 square feet. Some additional considerations before you begin plugging numbers into the paint calculator include:

  • Unpainted drywall absorbs more paint.
  • Apply two coats of paint to unfinished, patches or dark-colored surfaces colors.
  • Add tint to white primer when paints when painting over dark colors. Use a tint shade that closely matches the paint color.

Remember, two quarts of paint typically cost the same as one gallon.

Paint Calculation: Walls, Doors, Windows, and Trim

When computing the area for a solid wall, use your paint calculator to multiply the wall’s width times height. For example, a solid wall that measures 14 feet (wide) by 10 feet (height) has an area of 140 square feet. For walls that contain baseboards, doors, windows, crown molding, and other trim, calculate the surface area of each component separately.

  • How to measure around doors – Find the surface area for a solid wall. Then, calculate the area of each door. Subtract the area of the door from the surface area of the wall. Next, find the surface of the trim and subtract that number from the wall’s surface area.
  • How to measure around windows - Measure the wall to finds its total area. Calculate the area of each window – the window frame and the glass. Subtract the window area from the square footage for the walls. Compute the area of the windows separately.

You will likely used a different color and finish for the trim, which includes windows, doors, chair rails, molding, and baseboards. Measure the length of trim. Then multiply it by or1/2 foot or .5.

Ceilings and Trim

Calculate the surface area of the ceiling by multiplying the width times length. A ceiling that measures 15 feet by 15 feet requires you to buy enough paint to cover an area of 225 square feet. For an average surface, you would need at least one gallon of paint, plus an additional one quart, if you intend to cover the ceiling with two coats.

Exterior Paint Calculations

To figure out how much paint you need to paint the exterior (body) of the home, calculate the perimeter-- the distance around (the foundation) of the home. Next, measure the height of the home, from the foundation to the roofline. Multiply the perimeter times height to obtain the total square footage. For estimation purposes, it helps to know that the average exterior wall has a height of nine feet, for each story. Perform separate calculations for porches, gables, sheds or other attachments.

Contact the experts at Five Star Painting to help you calculate the amount of paint