How to Estimate Interior Paint for a Home

Measuring a room

• 1

  Use a large measuring tape to measure from the floor to the ceiling. This is your ceiling height.

• 2

  Measure the walls in the room. Add the "running feet" of all four walls to the number of ceiling height. This will give you the square feet of the wall surface. For example, if you have a 10- x 12-foot room with a 10-foot ceiling, the running feet of the walls would be 10+10+12+12, or 44. Multiply 44 x 10 and you have 440 square feet of wall space in the room. Next, measure the windows and doors that will not be painted and subtract these areas from your total.

• 3

  Purchase more primer/sealer if you are painting on new drywall. Primer will generally cover between 350 and 400 square feet per gallon. However, if the drywall has never been painted, it will absorb more paint. In this case, you will likely need three gallons in order to cover two coats with primer.

• 4

  Consider the color you've chosen for your base coat before deciding on the amount of paint to purchase. Base-coat paint will cover 350 to 400 square feet per coat. If you're painting a pale color over a white base, you may get by with one coat. However, the deeper the color, the more coats you'll require. For a base coat of red, dark green, navy or black, you'll need three or four coats. In this case, purchasing a five-gallon pail will give you the best value for your money. Don't skimp on paint because you'll want to have some left over for touch-ups for high-traffic areas.

• 5

  Repeat these steps for each room you are painting, and you'll be able to determine the quantity of paint you'll need for an entire home.