A roof-pitch chart is a convenient presentation of the same rise-and-run geometry used by the calculator. Values should be understood as mathematical conversions, not as permission to use a particular roofing material at that slope.
Common roof pitches: rise/run, degrees and slope factor
The reference page should make common conversions scannable without competing with the interactive calculator.
| Rise : run | Degrees | Slope factor |
|---|---|---|
| 1:12 | 4.8° | 1.003× |
| 2:12 | 9.5° | 1.014× |
| 3:12 | 14.0° | 1.031× |
| 4:12 | 18.4° | 1.054× |
| 5:12 | 22.6° | 1.083× |
| 6:12 | 26.6° | 1.118× |
| 7:12 | 30.3° | 1.158× |
| 8:12 | 33.7° | 1.202× |
| 9:12 | 36.9° | 1.250× |
| 10:12 | 39.8° | 1.302× |
| 12:12 | 45.0° | 1.414× |
| 16:12 | 53.1° | 1.667× |
Roof pitch quick reference
Common rise-to-run ratios visualized on the same 12-unit run.
What matters
- Pitch expressed as x:12 means x units of rise for 12 units of horizontal run.
- Angle comes from arctangent(rise/run).
- Area multiplier converts horizontal projected area to sloped plane area for a simple roof plane.
- Always check the selected roofing system’s current installation instructions and applicable project requirements.
How to use this page
Use the page as a decision or verification layer, then follow the linked calculator when you need project-specific arithmetic. Values that vary by product, moisture, local rule or job condition are identified as variables rather than presented as universal facts.
For work controlled by plans, specifications, permits, manufacturer instructions or professional design, those project-specific documents take precedence over this general reference.
Public corpus v1 · Method and scope reviewed for launch on 2026-08-13.
Roof pitch chart: compare rise/run, degrees and slope multipliers
A roof pitch chart lets the same slope be read in several useful forms. Rise/run is convenient for field measurement, degrees are useful for angle comparisons, and the slope multiplier is useful for converting horizontal dimensions into sloped dimensions.
Read pitch as rise over run
A 6:12 pitch rises 6 units for every 12 units of horizontal run. Because it is a ratio, the units cancel as long as rise and run use the same unit. The angle is the arctangent of rise divided by run.
The pitch multiplier is the sloped rafter-length factor for a unit of horizontal run and can also be used to convert plan area to roof surface area for a simple plane.
degrees = arctan(rise ÷ run); multiplier = √(rise² + run²) ÷ runUse the chart for cross-checking
Charts are useful for checking calculator outputs and for quickly comparing common pitches. For precise work, calculate from the measured rise and run rather than selecting the nearest visual example.
A roof with several slopes should be handled plane by plane when the geometry feeds into material quantities.
A pitch value is not a material approval
Roof-covering systems can have minimum-slope requirements and assembly-specific details. Snow, drainage, underlayment and local requirements are not determined by the chart.
Use the chart to describe geometry, then check product and project requirements separately.
Verify before you use the result
- Treat the chart as geometry, not a material approval table.
- Check product-specific minimum/maximum slope guidance separately.
- Use separate calculations for roof planes with different pitches.
Questions that come up before the next step
What does 4:12 roof pitch mean?
It means 4 units of vertical rise for every 12 units of horizontal run.
Why use a roof pitch multiplier?
It converts horizontal plan dimensions to sloped dimensions, which helps estimate roof surface area.
Is a pitch chart accurate enough for ordering materials?
It is useful for reference and cross-checking. For ordering, use measured project dimensions and the calculator rather than a visual estimate of pitch.
Primary and official references
Sources support the method and scope boundaries; project-specific requirements still need applicable product, supplier or local documentation.
Roof-system slope limits vary by system and project; slope is a design and drainage consideration.