What is a 7/12 pitch in roofing?

A 7/12 pitch means that for every 12 horizontal units, the roof rises 7 vertical units, creating a slope that is approximately 30 degrees.

What is a multiplier in roof calculations?

A multiplier is a numerical factor used to determine dimensions related to the roof's slope, such as calculating the rise or the length of rafters based on the pitch.

A plumb cut is an angled cut made at the top of a rafter, allowing it to fit properly against the ridge board of the roof.

7/12 gable rafter on a 16 ft span

Learn about gable roofs with a 7/12 pitch, including key concepts like multipliers, plumb cuts, and considerations for snow load sizing.

Formula SSC-2026.1

7.00 / 12 · 30.26°

Pitch angle

30.26°

Multiplier 1.1577

Common rafter

10 ft 4 3/16 in

Tail 1 ft 1 7/8 in

Cuts

30.26° plumb

59.74° seat

Roof area

538 ft²

5.38 squares

Shingle bundles

3 bundles per square + 10% waste

Sheathing / felt

19 sheets

2 underlayment rolls

Delivery weight

2,190 lb

993 kg · 70 lb bundles, 46 lb sheets, 28 lb rolls

Gable truss triangleLive scaled blueprint

Rise and run are scaled from the span, overhang, and pitch. The small triangle is the pitch ratio.

Bill of materials and shopping list
Item	Net	Waste	Order	Unit price	Line total	Source Spec Material / Tool
Architectural shingle bundles	5.38 squares	10%	18 bundles	USD	$756.00	Source Spec Material / Tool
4x8 CDX sheathing	16.8 sheets	10%	19 sheets	USD	$532.00	Source Spec Material / Tool
Underlayment rolls	538 ft²	overlap allowance	2 rolls	USD	$110.00	Source Spec Material / Tool
Ridge cap bundles	26.0 ft ridge	—	2 bundles	25 ft per bundle	—	Source Spec Material / Tool

Source links open a product search on the Amazon storefront for the selected currency. SiteSpecCalc may earn a commission. The link does not change the quantities above.

Side-by-side pitch comparison
Pitch	Degrees	Multiplier	Rafter	Squares	Bundles	Sheets
7.0/12	30.26°	1.158	10 ft 4 3/16 in	5.38	18	19
9.0/12	36.87°	1.250	11 ft 2 1/16 in	5.81	20	20

Show the deterministic formula

Angle = arctan(rise ÷ 12). Multiplier = √(1 + (rise ÷ 12)²). Gable run = span ÷ 2 − ridge thickness ÷ 2. Rafter length = (run + horizontal overhang) × multiplier.

Plumb cut = pitch angle. Seat cut = 90° − pitch angle. Area uses both slopes on a gable and one slope on a shed, and it includes a rake overhang equal to the eave overhang.

Bundles = ceiling of squares × 3 × 1.10. Sheets = ceiling of area × 1.10 ÷ 32. Rolls use 360 ft² effective coverage. Delivery weight plans 70 lb per bundle, 46 lb per sheet, and 28 lb per roll, then the header converts that pound total at 1 lb = 0.45359237 kg.

Contractor sign-off

Project: 7/12 gable rafter on a 16 ft span

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This sheet is an estimate for ordering and layout discussion. It is not a sealed design. Confirm the quantities with a licensed local professional and the authority having jurisdiction before you buy or build.

Engineering notes

A gable roof with a 7/12 pitch means that for every 12 horizontal units, the roof rises 7 vertical units. This pitch affects the overall height and design of the roof structure.

The multiplier is a factor used to calculate various dimensions related to the roof's slope, such as the total rise and the length of rafters. The plumb cut refers to the angled cut made at the top of the rafter, which allows it to fit snugly against the ridge board. It's important to note that snow load considerations are not included in this basic sizing discussion and should be evaluated separately based on local building codes and environmental conditions.

Code reference

Consult local building codes for specific requirements regarding snow load and structural integrity.

Field questions

What is a 7/12 pitch in roofing?: A 7/12 pitch means that for every 12 horizontal units, the roof rises 7 vertical units, creating a slope that is approximately 30 degrees.
What is a multiplier in roof calculations?: A multiplier is a numerical factor used to determine dimensions related to the roof's slope, such as calculating the rise or the length of rafters based on the pitch.
What is a plumb cut?: A plumb cut is an angled cut made at the top of a rafter, allowing it to fit properly against the ridge board of the roof.
Why is snow load not sized in this explanation?: Snow load sizing is not included in this basic discussion and should be evaluated separately based on local building codes and environmental conditions.