Estimates and Squares: How Many Shingles Will I Need?

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Hi, my name is Robert Kinghorn & I am a roofing contractor in Newnan, GA. Here is a quick article to help you out.

If you're a roofer or a DIY'er you want to know exactly how much material you'll need on a given job. Specifically you want to be as close as humanly possible so you have very little leftover material. The average trip fee just to pick up more shingles probably costs an hour in lost time, and $20 in gas!


Here are some tips and trick on how to get the most accurate estimates for your roofing jobs.


1. Eagleview.  If you’re not using Eagleview technologies you’re missing out. They provide a detailed report of EVERYTHING you can think of on a roof, including the number of squares, and linear feet of rakes, eaves, and even valleys. The reports vary in cost, also depending how often you order from them, but they save boatloads of time and make your measurements EXACT.
Eagleview will also break down the roof by facets, protrusions, and even has an option to get exact measurements for the walls if you’re doing a siding job.
Eagleview however will not and cannot tell you some crucial items:
Whether or not the chimney has a cricket.
How many pipe jacks/vents there are and what size each penetration is.
If there are valley metals.
If drip edge and gutter apron are present.
If the chimney or siding has or needs flashing.
You’ll need to have someone on site and on the roof to take photos and measurements of those particulars.
property facts

Apps: Work Smarter, Not Harder

2. Using an app like or dozens of others like the one at Better Homes & Gardens will give you an immediate break down of how many bundles of shingles are needed once you enter the number of squares from your Eagleview.

Bundles of Shingles

3. In terms of ordering shingles themselves, roof shingles are sold by both the bundle and estimated by the square. 1 square of shingles is the amount needed to cover 100 sq. ft. of roof. Shingles come in wrapped bundles designed to be light enough for a person to carry, so heavier shingles require more bundles per square.
Three bundles to a square is most common, which applies to most three-tab strip shingles and laminated shingles. When shingles are three bundles to the square, there are 29 standard-sized shingles (12 in. by 36 in.) in each bundle. Unless you’re installing a extremely high grade shingle (e.g. Owens Corning Berkshire which are 360 lbs a square) you should be fine.
Here’s the actual math: To determine the number of squares on a roof, divide its total # of square feet by 100. An average roof size is about 30 squares so (3,000 ÷ 100 = 30). This means you would need 30 squares of shingles to replace that roof. The most common type of shingle, called a three-tab or strip shingle, is generally packaged three bundles per square so you would need about 90 bundles.
Happy Measuring!