How to Estimate Paint Coverage Per Square Foot

If you are planning to paint your home, it may be a good idea to calculate the square footage of each room to determine the amount of paint you need for the project. With some simple area formula calculations, you can estimate paint coverage per square foot for any paint project.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Pen
• Paper
• Tape measure
• Calculator

1. Measure the width, length and height for all rooms you wish to paint. As an example, estimate paint coverage per square foot for a room that is 12 feet by 11 feet and a height of 8 feet. The room has a flat ceiling, two doors that are each 21 square feet and 2 windows that are each 12 square feet. In this example, the calculations are for one coat of paint.

2. Calculate the area for the ceiling by using the formula (Length X Width). For this example, the area of the ceiling is 12X11= 132 square feet. Note that for sloped or triangular shaped ceilings the formula is (Base X-Height)/2. Realize you omit this calculation if the ceiling requires no painting.

3. Add the total distance or perimeter of each wall together. For a 12 foot by 11 foot room, it is 11+11+12+12=46 feet. Multiply 46 feet by the height of 8 feet to find the total wall area which is 46 feet x 8 feet = 368 square feet.

4. Subtract from the total wall area of 368 square feet found in Step 3, the total door and window areas to determine the actual amount of wall area you need to paint. In this example, there are two windows (2X12 square feet)= 24 square feet and two doors (2 X21 square feet)= 42 square feet, so the actual amount of wall area is 368 square feet -24 square feet - 42 square feet = 302 square feet.

5. Use the calculations for ceiling area (132 square feet.) from Step 2 and the actual wall area (302 square feet) from Step 4 and add them to get 434 square feet. Note that this calculation is only if you use the same paint for walls and ceiling.

6. Estimate the paint coverage per square foot by dividing 434 square feet by 350 square feet which is 1.24 gallons. For this example, you may use the figure 350 square feet as the estimated square feet covered by one gallon of paint (this value may vary and depends on the type of paint used). You should buy 2 gallon for this project. Realize that you need to add more paint for either two coats of paint or if the walls are textured.

7. Determine the amount of paint needed for trim or molding by measuring the total length in feet and multiplying by ½ foot (estimated width of the trim). From Step 3, you get 46 feet for the total length. Multiply 46 feet x 1/2 foot = 23 square feet and then divide by 350 square feet as in Step 6 to get the quantity of paint as .065 of a gallon. Add this quantity to the quantity in Step 6 only if you use the same paint for the molding or trim as well.

Tips & Warnings

• There are many online calculators you can use for these calculations but they may include a 10 percent waste allowance (see Resources).
• Note that paint coverage per square footage estimations may vary between 300 to 400 square feet depending on the type of paint.
• These calculations are for using paint rollers or brushes. If using a sprayer, then more paint is needed.
• It is wise to buy a bit of extra paint for any emergency re-touches to walls or ceilings.

Resources

• Get information here on a paint calculator.

[mhlittlestar]

on 1/11/2009 sir i need the actual formulla .how to calcolate my paint for example:100sft into 1 mm thick coat of paint then how i am able to calcolate the paint lts per sft used.
thanksa and regards manzoor hussain ,pakistan