Place your ladder into position and climb on to the roof.
Measure the length and height of the roof in feet.
Multiply the length of the roof times the height. The product of this measurement will give you the total square footage of the roof.
Divide the total square footage of the roof by 100 to estimate the number of "roofing squares" needed. A single "square" is equal to three bundles of roofing shingles. Round up to the higher number if the number of squares is a fraction. For example, four-and-a-half squares would be rounded up to five squares. This ensures that you will have enough shingles to cover the roof.
Multiply the number of squares by three. This figure will give you the exact number of bundles of shingles you will need for the job. Average bundles of shingles are approximately $25 to $30. Multiply the number of total bundles you will need by $30. This will give you the total cost for shingles for the roofing job.
