A gable roof's square footage is equal to that of a hip roof with the same dimensions. The difference is in the fewer amount of ridge capping you need and the amount you will waste will be less than that for a hip roof.

As a note:

But with all the different types available, not all packs are equal in the amount of pieces they contain, the length of the individual shingle and the square foot coverage per pack. Not all types of shingles can be used for the starter strip and the ridge capping needed or you could be using ridge caps to cover the top ridge and the hips. That is why this calculator requires "the square foot one pack will cover" and the results for starter strip and ridge capping is in lineal feet needed for those two items and is not included in the Total Packs Needed.

Instructions

1. Enter the length of the building. (feet+inches)
2. Enter the width of the building. (feet+inches)
3. Enter the overhang of the eaves. (inches)
4. Enter the pitch of the roof. (rise /12")
5. Enter the square foot one pack will cover. (sq. ft.)
6. Enter a waste factor. (percentage)

The Results

1. Roof Area = total square footage of the roof.
2. Ridge length = top ridge.
3. Starter Strip = the perimeter of the roof in lineal feet including the rakes.
4. Total Shingles Needed = the number of packs needed to cover the roof but does not add additional packs needed for ridge capping and starter strips.