# Shingles-per-square Questions on Contractor's Exam

Shingles can be thought of or rectangles with an area of 3 sf, with a length of 3’ and a height of 1’, out of which only .5 inches are usually exposed

To calculate the amount of shingles needed for roofing square, follow these instructions

- Calculate Area of Exposure: Area of Exposure(sf) = Length of Shingle (ft) x Exposed distance (in) / 12
- Use Area of Exposure to Calculate the Amount of Shingles needed Amount of Shingles Needed per Square = 100 sf / Area of Exposure (sf)

Example: What's the amount of shingles per square needed if you have 3' by 1' shingles with 5" of exposure.

- Area of Exposure = 3' x 5" / 12 = 1.25 sf
- Amount of Shingles Needed per Square = 100 sf / 1.25 sf = 80

Example: What's the amount of shingles per square needed if you have 4' by 1' shingles with 5" of exposure.

- Area of Exposure = 4' x 5" / 12 = 1.67 sf
- Amount of Shingles Needed per Square = 100 sf / 1.67 sf = 59.88 or 60