Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Cuts, breakage, and mistakes. 10% is standard.
Result
Roofing squares
13.8
Shingle bundles
42
Roof surface area (sq ft)
1,252
Material cost
$1,791
Labour cost
$2,755
Total project cost
$4,545
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter building length (ft).
- 2Enter building width (ft).
- 3Enter pitch (rise per 12).
- 4Enter shingles per square ($).
- 5Enter labour per square ($).
- 6Enter waste allowance (%) — Cuts, breakage, and mistakes. 10% is standard..
- 7Read your roofing squares on the right — it updates as you type.
- 8Hit Share to keep the scenario or send it to someone.
About this calculator
Roofers work in squares — 100 square feet each. Pitch matters: a 6/12 roof has about 12% more surface than its footprint, and a 12/12 has 41% more.
Worked example
Using the values the calculator loads with:
Inputs
- Building length: 40 ft
- Building width: 28 ft
- Pitch (rise per 12): 6
- Shingles per square: 130 $
- Labour per square: 200 $
- Waste allowance: 10 %
Results
- Roofing squares: 13.8
- Shingle bundles: 42
- Roof surface area (sq ft): 1,252.2
- Material cost: $1,790.64
- Labour cost: $2,754.84
- Total project cost: $4,545.48
What each field means
Inputs
- Building length (ft)
- The building length used in the calculation, measured in ft. Starts at 40 ft so you have a working example on load.
- Building width (ft)
- The building width used in the calculation, measured in ft. Starts at 28 ft so you have a working example on load.
- Pitch (rise per 12)
- The pitch (rise per 12) used in the calculation. Starts at 6 so you have a working example on load. Accepted range: 0–18.
- Shingles per square ($)
- The shingles per square used in the calculation, measured in $. Starts at 130 $ so you have a working example on load.
- Labour per square ($)
- The labour per square used in the calculation, measured in $. Starts at 200 $ so you have a working example on load.
- Waste allowance (%)
- Cuts, breakage, and mistakes. 10% is standard.
Results
- Roofing squares
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Shingle bundles
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Roof surface area (sq ft)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Material cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Labour cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total project cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the roofing calculator work?
Roofers work in squares — 100 square feet each. Pitch matters: a 6/12 roof has about 12% more surface than its footprint, and a 12/12 has 41% more. The underlying maths is: Roof area = Footprint × Pitch multiplier. Squares = Area ÷ 100, plus waste.
What do I need to enter?
6 values: building length, building width, pitch (rise per 12), shingles per square, labour per square, and waste allowance. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the roofing squares result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Roofing Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/roofing
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/roofing" target="_blank" rel="noopener">Roofing Calculator — RevenueLab</a> (2026).</p>
Source: [Roofing Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/roofing) (2026).