From this site

One project, every trade

Each calculator adds its lines to a single estimate — consolidated BOM, schedule and cash-flow included.

Open My Project →

Roof Squares Calculator

Convert a roof's plan area and pitch into roofing squares — the unit material is ordered and labour is quoted in.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax
Who is doing the work?

The standard allowance most suppliers and estimating guides assume for ordinary work.

Roofing squares

15.89 squares

High confidence

Geometry is exact for a plane roof. Hips, valleys and dormers add area beyond the plan projection, which the waste factor is there to absorb.

Slope factor
1.12 ×
True sloped area
1444.13 ft²
With waste
1588.54 ft²
Sloped area in ft²
1588.54 ft²
Pitch angle
26.57 °

For the dimensions entered, expect a roofing squares of 15.9. Note that roof plan area (footprint) sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. Set for United States against IRC 2024. The market selector changes both the units and the code cited.

Estimated cost — your price

This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • 1 roofing square = 100 ft² (9.2903 m²) of roof surface — universal North American roofing trade unit
  • Slope factor = √(1 + (rise/run)²); the multiplier from plan area to true sloped area

Your workspace

Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Frequently asked questions

What is a roofing square?
100 square feet of roof surface — 9.29 m². Shingles, underlayment and labour are all quoted per square across North America, and a bundle of architectural shingles typically covers a third of one. It is a unit of the sloped surface, not of the footprint.
Why does pitch change the area?
Because a sloped surface is longer than its horizontal projection. A 6:12 roof is 11.8% larger than its footprint; a 12:12 roof is 41.4% larger. Ordering against the footprint on a steep roof leaves you a long way short, and it is a mistake that only shows up on the last day.
How do I measure a roof I cannot get onto?
Take the footprint from the ground or from a plan, then measure the pitch from inside the loft against a rafter — the clinometer tool on this site does it from a phone. That combination gives the sloped area without anyone going up.