If you are planning to use siding on the exterior of your home, you will need to know the square footage of the area that will be covered. Calculating the square footage allows you to estimate the amount of materials you will need, the cost of those materials and the labor involved in the project. Measuring square feet of an area that will be covered with siding only takes a bit of effort and some simple calculations.
Things You'll Need
 Tape measure
 Calculator
 Paper
 Pencil

Sketch the sections of your home that will receive siding. It doesn't have to be an elaborate sketch, just a collection of rectangular and triangular portions of your house.

Use a tape measure to measure the length and width of each rectangular section on the exterior of your home that will be covered. Measure the height and base of each triangular section.

Record the measurements for each section on your sketch.

Find the area of the rectangular sections by multiplying the length and the width.

Find the area of the triangular sections by multiplying the base times the height and then dividing by two.

Add the areas for each shape on the sketch of your home to find the total square feet.
References
 Photo Credit house siding 3 image by Psycience from Fotolia.com