# How to Figure Square Feet for Painting Walls brush in paint image by Vladislav Gajic from Fotolia.com
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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.

• Tape measure
• Calculator

## Rectangular Walls

Measure the length of the wall in feet.

Measure the height of the wall in feet.

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

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

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

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

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

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.

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.