Measurement
What is a square in roofing?
The unit that every roofing estimate is written in, and the reason a "30-square roof" has nothing to do with its shape.
Updated September 12, 2026 · Every figure links to its source · Sources
DefinitionMeasurementAlso called: square, roofing squares
Roofing square — the unit of area used in the roofing trade, equal to 100 square feet of roof surface, in which materials are sold and installation is priced; the NRCA glossary defines the square so, and the Asphalt Roofing Manufacturers Association uses it in its shingle coverage figures.
What it is
A square is a ten-foot by ten-foot patch of roof. A roof with 2,400 square feet of surface is a 24-square roof; a bundle of shingles covers a stated fraction of a square, so that a given number of bundles — commonly three for a standard laminated shingle, more for heavier products — makes up a square; underlayment, ice barrier and starter strip are likewise sold in rolls rated by the square. Labour is quoted per square, at one rate for walkable roofs and a higher rate for steep ones.
The surface area is larger than the footprint, because the roof is sloped. The footprint measured from the ground or a satellite image is multiplied by a pitch factor — small for a 4:12 roof, considerable for a 12:12 — and the directory's roofing squares calculator does that arithmetic from the footprint and the pitch. Hips, valleys, dormers and the cutting they require add a waste factor, typically a percentage on top of the measured squares, which the estimate should state.
Why it matters
The square count is the number every other number in a quote multiplies. If one contractor measures 28 squares and another 34 for the same roof, the price gap has nothing to do with quality, and the homeowner can settle the question by asking for the measurements — the footprint dimensions, the pitch and the waste factor — and checking them. Aerial-measurement reports, which many contractors now buy per address, give a square count with a diagram and are worth asking to see.
Bundles matter for the same reason. The ARMA and the manufacturers publish the bundles per square for each product; a quote that lists the bundles ordered lets you check the squares it implies. The directory's nails-per-shingle entry covers the other per-square figure that decides the wind warranty.
What it costs and who does it
The price per square is the figure contractors compare among themselves and the one a homeowner should ask for, because it makes quotes comparable across roofs of different size; it bundles the shingle, the underlayment, the labour and the disposal, with flashing, decking, ventilation and steep-work surcharges as separate lines. Any roofing contractor measures in squares; the directory's guide to a new roof installation explains how the count turns into a contract price.
Frequently asked questions
Short answers; the sections above carry the detail and the sources.
How many square feet is a roofing square?
How many bundles of shingles are in a square?
How do I calculate the squares on my roof?
Next step
Find a roofer who does this
Ask every bidder for the squares, the pitch and the waste factor, and the quotes will explain themselves. The directory lists roofing contractors by state and city.
Sources
- Roofing glossary — National Roofing Contractors Association (NRCA)
- Asphalt Roofing Manufacturers Association — ARMA