🧭 Roof Pitch to Degrees Calculator
Pitch ⇄ degrees, percent grade and area multiplier
Enter a pitch as rise over 12, or enter an angle in degrees to work backwards. You get the angle, percent grade, area multiplier, hip/valley multiplier and — if you add a footprint — the true sloped roof area in square feet and roofing squares.
Smart Roofing Calculator — Roof Pitch to Degrees Calculator — smartroofingcalculator.com/roof-pitch-to-degrees/ — printed
6 means a 6:12 pitch
Adds true sloped area and squares
📐 Pitch is rise per 12 inches of run — 6:12 means 6 in of rise every 12 in across.
🛠️ How This Calculator Works
Roof pitch and roof angle are the same steepness expressed differently. Pitch is the vertical rise in inches for every 12 inches of horizontal run, so dividing rise by 12 gives the tangent of the roof angle. Taking the arctangent of that ratio returns the angle in degrees. The area multiplier — the square root of one plus the ratio squared — is what turns a flat footprint into true sloped surface area, and the hip/valley multiplier does the same for diagonal members.
📐 Formula
Degrees = arctan(Rise ÷ 12) | Rise = tan(Degrees) × 12 | Grade % = (Rise ÷ 12) × 100 | Area Multiplier = √(1 + (Rise ÷ 12)²) | Hip Multiplier = √(2 + (Rise ÷ 12)²)📝 Example Calculation
A 7:12 roof over a 1,600 sq ft footprint: • 7 ÷ 12 = 0.5833 • Angle: arctan(0.5833) = 30.26° • Grade: 58.3% • Area multiplier: √(1 + 0.5833²) = 1.1577 • Sloped area: 1,600 × 1.1577 = 1,852 sq ft = 18.52 squares
💡 Pro Tips from Roofers
- Measure rise over a full 12 in of level, not over a shorter span — small errors get multiplied.
- Never apply the pitch multiplier to an area that is already sloped; you will double count.
- Hip and valley lengths use the hip multiplier, not the area multiplier.
- Structural drawings sometimes use rise over full span; roofing always uses rise over 12.
- Round pitch to the nearest half inch when ordering — manufacturers publish specs that way.
❓ Frequently Asked Questions
What is a 6/12 roof pitch in degrees?
A 6:12 pitch is 26.57 degrees. It comes from arctangent(6 ÷ 12) = arctan(0.5). In percent grade that is 50%, and its area multiplier is 1.1180.
How do I convert roof pitch to degrees?
Divide the rise by 12 to get the tangent of the angle, then take the arctangent. For an 8:12 roof: 8 ÷ 12 = 0.6667, arctan(0.6667) = 33.69 degrees. This calculator does it both directions, so you can also enter degrees and get the nearest rise-over-12 pitch.
What roof pitch is 45 degrees?
Exactly 12:12 — rise equals run. Its percent grade is 100% and the area multiplier is 1.4142 (the square root of 2), so a 12:12 roof has about 41% more surface than its footprint.
What is the difference between pitch, slope and grade?
In US roofing they describe the same steepness three ways. Pitch (or slope) is written as rise:12. Grade is that ratio as a percentage. The angle in degrees is the trigonometric version. Structural drawings sometimes use pitch as rise over full span, which halves the number — check which convention a drawing uses.
What is the minimum roof pitch for asphalt shingles?
Building codes generally allow asphalt shingles down to 2:12 (about 9.5 degrees), but from 2:12 up to 4:12 a doubled or fully self-adhered underlayment is normally required. Below 2:12 you need a membrane roof such as TPO, EPDM or modified bitumen instead.
How do I find my roof pitch without climbing up?
Hold a level horizontally against a gable end or inside the attic against a rafter, mark 12 inches along the level, then measure straight down from that mark to the rafter or roof line. That vertical measurement in inches is your rise over 12.
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We build free, accurate construction calculators for homeowners and contractors. This article is part of our roofing knowledge base — we also publish guides and tools for other home improvement projects:
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Roof pitch to degrees conversion chart
| Pitch | Degrees | Percent grade | Area multiplier |
|---|---|---|---|
| 1:12 | 4.76° | 8.3% | 1.0035 |
| 2:12 | 9.46° | 16.7% | 1.0138 |
| 3:12 | 14.04° | 25.0% | 1.0308 |
| 4:12 | 18.43° | 33.3% | 1.0541 |
| 5:12 | 22.62° | 41.7% | 1.0833 |
| 6:12 | 26.57° | 50.0% | 1.1180 |
| 7:12 | 30.26° | 58.3% | 1.1577 |
| 8:12 | 33.69° | 66.7% | 1.2019 |
| 9:12 | 36.87° | 75.0% | 1.2500 |
| 10:12 | 39.81° | 83.3% | 1.3017 |
| 11:12 | 42.51° | 91.7% | 1.3566 |
| 12:12 | 45.00° | 100.0% | 1.4142 |
| 14:12 | 49.40° | 116.7% | 1.5366 |
| 16:12 | 53.13° | 133.3% | 1.6667 |
| 18:12 | 56.31° | 150.0% | 1.8028 |
Why the angle matters on a real job
The angle is not trivia. It decides which materials are allowed, how the underlayment must be detailed, how much labour the job carries, and how safely a crew can move. Below 2:12 shingles are out entirely. Between 2:12 and 4:12 you keep shingles but the underlayment requirement doubles. Past roughly 30 degrees most crews price in roof brackets and staging, which is why two roofs of identical square footage can be quoted thousands of dollars apart.
Minimum pitch by roofing material
- Asphalt shingles: 2:12 minimum, doubled underlayment from 2:12 to 4:12.
- Standing seam metal: commonly permitted from 1:12 (check the panel's listing).
- Exposed-fastener metal panels: usually 3:12 and up.
- Concrete and clay tile: generally 2.5:12 up, with underlayment upgrades below 4:12.
- TPO, EPDM and modified bitumen: designed for slopes under 2:12 with positive drainage.
Always confirm against the specific product's installation instructions and your local code — the listing governs the warranty.
Is your pitch steep enough for shingles? The minimum roof pitch calculator checks it against the IRC minimum for every roof covering.
See every conversion at once in the roof pitch chart in degrees, including half pitches such as 6.5/12.
Working on the roof? See the roofing shoes and boots guide for footing by pitch.
Want the reading without the maths? Our pitch finder roundup compares magnetic gauges, digital inclinometers and speed squares.
🔗 Related Roofing Calculators
- Roof Pitch Calculator — Find pitch from rise and run measurements
- Roof Pitch Chart — Full reference table of common pitches
- Pitch Multiplier Chart — Area and hip/valley multipliers
- Roof Slope Calculator — Rise, run and slope length
- Roof Area Calculator — Apply the multiplier to your footprint
- Shingles Calculator — Bundles once you know the sloped area
· Reviewed by the Smart Roofing Calculator editorial team