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The roof angle measured from horizontal, in degrees.
Take this from a digital inclinometer laid on the rafter or the sheathing, not on the finished covering — tiles and shingles sit at a slightly different plane and will bias the reading.
Equivalent pitch
6.928 in per 12 in
Rise per 12 = tan(angle) × 12. Round to the nearest common pitch when ordering — material schedules and minimum-slope tables are written against whole ratios.
They open the calculator with your figures already in it
Degrees to Roof Pitch Calculator: 6.93 in per 12 in — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Inverse of the pitch definition: rise per 12 units of run = tan(angle) x 12
- Manufacturer minimum slopes are commonly stated in rise-per-12, e.g. 2:12 for many asphalt shingle systems with additional underlayment
Inputs used
- Measured angle (°)
- 30
Confidence note: Rise per 12 = tan(angle) × 12. Round to the nearest common pitch when ordering — material schedules and minimum-slope tables are written against whole ratios.
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This result is a specification — 6.928 in per 12 in — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-08-26 · in the site-wide review of 2026-09-06 · v1.0.0
Regulatory standards & verification citations2
- Inverse of the pitch definition: rise per 12 units of run = tan(angle) x 12
- Manufacturer minimum slopes are commonly stated in rise-per-12, e.g. 2:12 for many asphalt shingle systems with additional underlayment
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Surveying an existing roof gives an angle, but almost everything you then need to buy is specified against a ratio: shingle manufacturers publish minimum slopes as 2:12 or 4:12, flashing details assume standard pitches, and material take-off tables are indexed the same way. Converting the measured angle back into rise-per-12 is what lets a survey talk to a supplier. Expect an untidy number — a real roof rarely sits on a whole ratio — and round to the nearest standard pitch for ordering while keeping the measured figure for cutting. Where the rounding crosses a manufacturer's minimum slope threshold, round down rather than up: a covering installed below its stated minimum slope is a warranty problem and, in driving rain, a leak.