Roof pitch and slope
Roof Pitch Chart
Last updated October 14, 2026 · Method · Corrections
Enter measured dimensions to calculate roofing quantities.
Read rise-in-12 as vertical rise over twelve level units. Degrees measure angle; percent is rise divided by run times one hundred. The area factor converts matching plan area to surface. The table rounds only for display. For a noninteger measured slope, use the pitch calculator and keep its exact input instead of choosing the nearest row.
Sections5
This roof pitch chart converts integer rise-in-12 ratios to degrees, percent slope and roof-area factors. It includes zero through twenty-four rise units per twelve level units. The table is a math reference. It does not assign a covering or classify a roof as safe to walk on.
Roof pitch chart: ratio, degrees and area factor
The table below is computed from atan(rise / 12) for angle and √(1 + (rise / 12)²) for area factor. Degrees display to two decimals, percent to two decimals and factor to four. These are derived numbers, checked October 14, 2026.
| Rise-in-12 | Degrees | Percent | Area factor |
|---|---|---|---|
| 0:12 | 0.00 | 0.00% | 1.0000 |
| 1:12 | 4.76 | 8.33% | 1.0035 |
| 2:12 | 9.46 | 16.67% | 1.0138 |
| 3:12 | 14.04 | 25.00% | 1.0308 |
| 4:12 | 18.43 | 33.33% | 1.0541 |
| 5:12 | 22.62 | 41.67% | 1.0833 |
| 6:12 | 26.57 | 50.00% | 1.1180 |
| 7:12 | 30.26 | 58.33% | 1.1577 |
| 8:12 | 33.69 | 66.67% | 1.2019 |
| 9:12 | 36.87 | 75.00% | 1.2500 |
| 10:12 | 39.81 | 83.33% | 1.3017 |
| 11:12 | 42.51 | 91.67% | 1.3566 |
| 12:12 | 45.00 | 100.00% | 1.4142 |
| 13:12 | 47.29 | 108.33% | 1.4743 |
| 14:12 | 49.40 | 116.67% | 1.5366 |
| 15:12 | 51.34 | 125.00% | 1.6008 |
| 16:12 | 53.13 | 133.33% | 1.6667 |
| 17:12 | 54.78 | 141.67% | 1.7341 |
| 18:12 | 56.31 | 150.00% | 1.8028 |
| 19:12 | 57.72 | 158.33% | 1.8727 |
| 20:12 | 59.04 | 166.67% | 1.9437 |
| 21:12 | 60.26 | 175.00% | 2.0156 |
| 22:12 | 61.39 | 183.33% | 2.0883 |
| 23:12 | 62.45 | 191.67% | 2.1619 |
| 24:12 | 63.43 | 200.00% | 2.2361 |
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Use the roof pitch chart with the right area basis
Multiply plan level area by the factor. A measured sloped surface already includes pitch and needs no second multiplier. For example, 12:12 gives forty-five degrees and a factor of about 1.4142. It does not double the area despite being a one-hundred-percent slope.
Use the roof pitch calculator for fractional rise or a measured angle. Read how to calculate roof pitch when the source uses full span or sloped length. The historical rise-to-span meaning differs from this chart's rise-to-run basis.
Covering limits and printable reference
GAF's shingle slope guidance and each exact metal system's documents set conditions that this chart cannot infer. Print the table with its formulas and date. Material choice, drainage and roof condition remain separate checks.
Frequently asked questions
What is a 6:12 roof pitch in degrees?
The angle is about 26.57 degrees when rounded to two decimals. Its exact rise-to-run ratio is one-half; inverse tangent gives the angle. The chart rounds the roof area factor to about 1.1180. For a measured footprint, use the calculator so the area conversion retains unrounded values internally.
What is a roof pitch multiplier?
It is the factor that converts level plan area to sloped roof surface for the stated pitch. The factor is the square root of one plus the slope ratio squared. It belongs to area, not a price or waste allowance. Do not multiply an already measured roof surface by it again.
How do I convert roof pitch to degrees?
Divide rise by level run, take the inverse tangent and convert the result to degrees. For rise-in-12, the denominator is twelve. A measured angle can also be entered directly in the pitch calculator. Keep the source's ratio meaning clear; a rise-over-full-span figure is not the same input as rise over run.
Does the chart recommend a roofing material?
No. It only converts slope units and area factors. Exact maker instructions, assembly details and local rules govern a covering's fit. A numeric row does not show drainage performance or roof access safety. Use the material-specific minimum-pitch guides and the actual system documents before treating a slope as suitable for a covering.
Verdict: use the measured row basis
Keep the roof pitch chart as a unit reference. Use the pitch calculator for exact or noninteger inputs, and the roofing calculator for area. The method page records the formulas and corrections.