### Things You'll Need

Tape measure

Calculator

Calculating square footage is a matter of using simple math. The main problems occur with windows or doors, and walls with a triangle shape. The process is simple with a tape measure and a calculator. Once you calculate the square footage of the walls, you will be able to buy enough paint to cover them. When taking measurements and painting walls, move all furniture away from the walls.

## Rectangular Walls

## Step 1

Measure the length of the wall in feet.

## Step 2

Measure the height of the wall in feet.

## Step 3

Multiply the height of the wall by the length of the wall. This number is the square footage of the wall.

## Step 4

Perform the same measurements and calculations on any windows or doors located on the wall.

## Step 5

Subtract any square footage of windows or walls from the wall's total square footage to arrive at the square footage of wall surface needing paint.

## A Wall with a Triangle Portion

## Step 1

Calculate the square footage of the rectangular portion of the wall.

## Step 2

Measure the height of the triangle portion of the wall in feet.

## Step 3

Multiply the height of the triangle portion of the wall by the length of the triangular section. Then divide the answer by two. This number is the square footage for the triangle portion of the wall.

## Step 4

Add the rectangular square footage and the triangular square footage of the wall. Then subtract the square footage of any windows or doors to arrive at total square feet of wall needing paint.

#### Carter McBride

Carter McBride started writing in 2007 with CMBA's IP section. He has written for Bureau of National Affairs, Inc and various websites. He received a CALI Award for The Actual Impact of MasterCard's Initial Public Offering in 2008. McBride is an attorney with a Juris Doctor from Case Western Reserve University and a Master of Science in accounting from the University of Connecticut.