Project Tools

Paint Calculator

Area Measurements
Wall (in ft.) Height x Room Perimeter
Ceiling (in ft.) Length x Width
Sloping Wall (in ft.) Height x Base
Total Painting Area: sq. ft.
Total Gallons of Paint Needed: gallons


Tips on Measuring for Paint
Before you begin, take the room measurements in the list below - round to the nearest foot. If you have cathedral ceilings that create sloping walls, follow the special case instructions on how to derive this square footage.

To ensure you will have enough paint, do not worry about excluding areas not to be painted, such as windows and doors. Additionally, a 10 percent waste allowance is automatically added to the total.

  • 1. Wall Height
    Measure from floor to ceiling.
  • 2. Wall perimeter for areas you plan to paint
    Measure the length of each wall. Add all length figures together to obtain the total horizontal distance, or perimeter.
  • 3. Ceiling width and length
    Omit if you do not plan to paint your ceiling.
  • 4. Sloping walls
    Sloping walls form a triangular wall space. To calculate a triangle's square footage, multiply the length of the wall at the base of the triangle by its height and divide by 2.


Homeowner Tip - One gallon of paint covers approximately 400 square feet.

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