Roof Pitch Chart: Degrees, Slope & Pitch Factor
A roof pitch chart converts a roof's rise-over-run ratio into other ways of expressing the same slope, including degrees, slope percentage and pitch factor. For example, a 6:12 roof pitch rises 6 units for every 12 units of horizontal run. That is equivalent to an angle of 26.57°, a 50% slope and a pitch factor of 1.118.
Use the chart below for quick conversions from 0.5:12 to 24:12. If your roof does not match one of these standard increments, use our Roof Pitch Calculator to calculate the exact value from the measurements you have.
On this page
Roof Pitch Chart
The table converts each roof pitch into its equivalent angle from horizontal, percentage slope and pitch factor.
| Roof Pitch | Angle | Slope | Pitch Factor |
|---|---|---|---|
| 0.5:12 | 2.39° | 4.2% | 1.001 |
| 1:12 | 4.76° | 8.3% | 1.003 |
| 1.5:12 | 7.13° | 12.5% | 1.008 |
| 2:12 | 9.46° | 16.7% | 1.014 |
| 2.5:12 | 11.77° | 20.8% | 1.021 |
| 3:12 | 14.04° | 25.0% | 1.031 |
| 3.5:12 | 16.26° | 29.2% | 1.042 |
| 4:12 | 18.43° | 33.3% | 1.054 |
| 4.5:12 | 20.56° | 37.5% | 1.068 |
| 5:12 | 22.62° | 41.7% | 1.083 |
| 5.5:12 | 24.62° | 45.8% | 1.100 |
| 6:12 | 26.57° | 50.0% | 1.118 |
| 6.5:12 | 28.44° | 54.2% | 1.137 |
| 7:12 | 30.26° | 58.3% | 1.158 |
| 7.5:12 | 32.01° | 62.5% | 1.179 |
| 8:12 | 33.69° | 66.7% | 1.202 |
| 8.5:12 | 35.31° | 70.8% | 1.226 |
| 9:12 | 36.87° | 75.0% | 1.250 |
| 9.5:12 | 38.37° | 79.2% | 1.275 |
| 10:12 | 39.81° | 83.3% | 1.302 |
| 10.5:12 | 41.19° | 87.5% | 1.329 |
| 11:12 | 42.51° | 91.7% | 1.357 |
| 11.5:12 | 43.78° | 95.8% | 1.386 |
| 12:12 | 45.00° | 100.0% | 1.414 |
| 12.5:12 | 46.17° | 104.2% | 1.444 |
| 13:12 | 47.29° | 108.3% | 1.474 |
| 13.5:12 | 48.37° | 112.5% | 1.505 |
| 14:12 | 49.40° | 116.7% | 1.537 |
| 14.5:12 | 50.39° | 120.8% | 1.569 |
| 15:12 | 51.34° | 125.0% | 1.601 |
| 15.5:12 | 52.25° | 129.2% | 1.634 |
| 16:12 | 53.13° | 133.3% | 1.667 |
| 16.5:12 | 53.97° | 137.5% | 1.701 |
| 17:12 | 54.78° | 141.7% | 1.735 |
| 17.5:12 | 55.56° | 145.8% | 1.769 |
| 18:12 | 56.31° | 150.0% | 1.803 |
| 18.5:12 | 57.03° | 154.2% | 1.838 |
| 19:12 | 57.72° | 158.3% | 1.873 |
| 19.5:12 | 58.39° | 162.5% | 1.908 |
| 20:12 | 59.04° | 166.7% | 1.944 |
| 20.5:12 | 59.66° | 170.8% | 1.980 |
| 21:12 | 60.26° | 175.0% | 2.016 |
| 21.5:12 | 60.84° | 179.2% | 2.052 |
| 22:12 | 61.39° | 183.3% | 2.088 |
| 22.5:12 | 61.93° | 187.5% | 2.125 |
| 23:12 | 62.45° | 191.7% | 2.162 |
| 23.5:12 | 62.95° | 195.8% | 2.199 |
| 24:12 | 63.43° | 200.0% | 2.236 |
How to Read a Roof Pitch Chart
A pitch such as 6:12 describes a right triangle formed by the roof slope.
The first number is the vertical rise. The second is the horizontal run.
So:
6:12 means the roof rises 6 units for every 12 units of horizontal travel.
Those units can be inches, feet, millimetres or any other consistent unit. A 6-inch rise over a 12-inch run has exactly the same angle as a 6-foot rise over a 12-foot run.
This is why a roof pitch ratio is independent of the measurement system.
What does a 6:12 roof pitch mean?
A 6:12 roof converts to:
- 26.57° roof angle
- 50% slope
- 1.118 pitch factor
These are not different roof slopes. They are different ways of expressing the same geometry.
Common Roof Pitches at a Glance
These common values are useful when you need a quick comparison without scanning the full table.
| Pitch | Angle | Slope |
|---|---|---|
| 2:12 | 9.46° | 16.7% |
| 4:12 | 18.43° | 33.3% |
| 6:12 | 26.57° | 50.0% |
| 8:12 | 33.69° | 66.7% |
| 10:12 | 39.81° | 83.3% |
| 12:12 | 45.00° | 100.0% |
One useful point to remember is that percentage slope is not the same as angle in degrees.
A 12:12 roof has a 100% slope, but its angle is 45°, not 100°.
The percentage describes the amount of vertical rise relative to horizontal run:
How the Roof Pitch Chart Is Calculated
Every value in the chart comes from the same right-triangle geometry.
If the roof pitch is written as x:12, then:
From that ratio, we can calculate angle, percentage slope and pitch factor.
Converting roof pitch to degrees
The roof angle is:
For an x:12 pitch:
The resulting angle is measured from the horizontal.
Converting roof pitch to percentage slope
Percentage slope is calculated as:
For a 6:12 pitch:
Calculating the pitch factor
The pitch factor is:
It represents the ratio between the sloping length and its corresponding horizontal projection.
Worked example: 6:12 roof pitch
Suppose the roof rises 6 units for every 12 units of horizontal run.
First:
The angle is:
Rounded to two decimal places:
The percentage slope is:
The pitch factor is:
6:12 = 26.57° = 50% slope = 1.118 pitch factor
That same calculation method is used for every row in the table.
Roof Pitch, Roof Angle and Slope Percentage
These terms are related, but they are not interchangeable units.
Roof pitch, in common US roofing use, is normally written as a rise over 12 units of horizontal run, such as 4:12 or 8:12.
Roof angle expresses that same slope in degrees measured above horizontal.
Percentage slope expresses vertical rise as a percentage of horizontal run.
For example:
8:12 pitch = 33.69° angle = 66.7% slope
Someone working from construction drawings may use an x:12 pitch, while another calculation or piece of software may use degrees or percentage. The chart simply lets you move accurately between those formats.
What Does the Roof Pitch Factor Tell You?
Pitch factor tells you how much longer a sloping roof surface is than its horizontal projection.
A 6:12 roof has a factor of approximately 1.118.
That means a horizontal distance of 10 ft corresponds to approximately:
along the slope.
The same relationship can help convert a horizontal projected area into the corresponding sloping surface area for a simple roof plane.
For example, if a roof plane has a horizontal projected area of 1,000 ft² and a 6:12 pitch:
That is the geometric sloping area represented by that projection.
It is not automatically the amount of roofing material you should order. Overhangs, dormers, valleys, intersecting planes, multiple pitches, openings and material waste can all affect the final quantity.
Low-Slope and Steep Roofs: Why the Context Matters
Terms such as low slope and steep roof are sometimes used as though they have one universal definition. In practice, the cutoff depends on why the roof is being classified.
For US construction fall-protection rules, OSHA defines a low-slope roof as one with a slope less than or equal to 4:12, and a steep roof as one with a slope greater than 4:12. Those definitions are specifically used in OSHA's safety regulations.
That does not mean 4:12 is a universal boundary for roofing products.
For example, the 2024 International Residential Code states that asphalt shingles are used on slopes of 2:12 or greater and requires additional underlayment provisions between 2:12 and 4:12. GAF likewise identifies 2:12 as the minimum slope for its shingles and calls for additional roof-deck protection on lower slopes, subject to applicable code and installation requirements.
So the safe way to use this chart is:
Use the chart to understand the geometry. Use the applicable code and the roofing manufacturer's instructions to determine what can be installed.
Need an Exact Pitch That Isn't in the Chart?
A reference chart works best when your pitch matches a standard increment.
Real roofs do not always cooperate.
You might measure a rise of 7⅜ inches over 12 inches, know the roof angle but not the rise, or have dimensions for a complete roof span instead.
In those situations, use the Roof Pitch Calculator rather than rounding your measurement to the nearest row. It can calculate the exact pitch from several combinations of known measurements and return the angle, percentage slope, x:12 ratio, rafter length and pitch factor.
Use the Roof Pitch Calculator →
Use the Roof Pitch Calculator →Roof Pitch Chart FAQs
What angle is a 4:12 roof pitch?
A 4:12 roof pitch is approximately 18.43°. It rises 4 units for every 12 units of horizontal run and has a slope of approximately 33.3%.
What angle is a 6:12 roof pitch?
A 6:12 roof pitch is approximately 26.57°. It is equivalent to a 50% slope and has a pitch factor of approximately 1.118.
What is a 12:12 roof pitch in degrees?
A 12:12 roof pitch is exactly 45° because the vertical rise and horizontal run are equal.
Is a 100% roof slope the same as 90°?
No. A 100% slope equals 45°.
Percentage slope is calculated as rise divided by horizontal run. When rise equals run:
A 90° line would be vertical and would not have a finite horizontal-run slope ratio.
Can I print the roof pitch chart?
Yes. Use the Print / Save PDF button near the top of this guide to keep a printable copy of the roof pitch chart without the website navigation, calculator CTAs or footer.
A note on using the chart
The values in this chart are mathematical conversions based on a right triangle. The reliability of any project calculation still depends on the accuracy of the measurements supplied.
For structural design, fall protection, code compliance, roofing-system selection or other project-specific decisions, use the applicable technical requirements and consult an appropriately qualified professional where necessary.