Complete Roof Pitch Multiplier Chart
This table shows every standard roof pitch with its corresponding angle in degrees, the pitch multiplier used to calculate actual roof area, and a description of how steep the pitch is.
| Pitch (Rise/Run) | Degrees | Multiplier | Category |
|---|---|---|---|
| 1/12 | 4.76° | 1.003 | Nearly flat |
| 2/12 | 9.46° | 1.014 | Low slope |
| 3/12 | 14.04° | 1.031 | Low slope |
| 4/12 | 18.43° | 1.054 | Standard low |
| 5/12 | 22.62° | 1.083 | Moderate |
| 6/12 | 26.57° | 1.118 | Standard |
| 7/12 | 30.26° | 1.157 | Standard |
| 8/12 | 33.69° | 1.202 | Steep |
| 9/12 | 36.87° | 1.250 | Steep |
| 10/12 | 39.81° | 1.302 | Very steep |
| 11/12 | 42.51° | 1.357 | Very steep |
| 12/12 | 45.00° | 1.414 | 45-degree |
| 13/12 | 47.29° | 1.474 | Extreme |
| 14/12 | 49.40° | 1.537 | Extreme |
| 15/12 | 51.34° | 1.601 | Extreme |
| 16/12 | 53.13° | 1.667 | Extreme |
| 17/12 | 54.78° | 1.734 | Extreme |
| 18/12 | 56.31° | 1.803 | Mansard |
| 19/12 | 57.72° | 1.873 | Mansard |
| 20/12 | 59.04° | 1.944 | Mansard |
| 21/12 | 60.26° | 2.016 | Extreme steep |
| 22/12 | 61.39° | 2.088 | Extreme steep |
| 23/12 | 62.45° | 2.162 | Extreme steep |
| 24/12 | 63.43° | 2.236 | Extreme steep |
How to Use the Pitch Multiplier
The pitch multiplier converts a flat (horizontal) roof footprint into actual sloped roof area. The formula is simple:
Actual Roof Area = Footprint Area × Pitch Multiplier
Example Calculation
Ranch-style home with 1,500 sq ft footprint at 6/12 pitch:
- Footprint area: 1,500 sq ft
- Pitch multiplier for 6/12: 1.118
- Actual roof area: 1,500 × 1.118 = 1,677 sq ft
- In roofing squares: 1,677 / 100 = 16.77 squares
Use the roof pitch calculator to compute this automatically with your measurements.
Roof Area Calculator
Footprint: 1,200 sq ft × 1.054 multiplier
1,265 sq ft
What Is Roof Pitch?
Roof pitch describes the steepness of a roof as a ratio of vertical rise to horizontal run. It is expressed as "X/12" where X is the number of inches the roof rises vertically for every 12 inches of horizontal distance.
For example, a 6/12 pitch means the roof rises 6 inches for every 12 inches (1 foot) of horizontal run. This is one of the most common residential roof pitches in the United States.
The pitch affects everything from material selection to installation difficulty to total material quantities. Steeper roofs require more material to cover the same footprint because the sloped surface area is larger. Read our complete guide on understanding roof pitch for more details.
How to Measure Your Roof Pitch
From the Attic (Safest Method)
Go into your attic with a 24-inch level and tape measure.
Place the level against the underside of a rafter, making it perfectly horizontal.
Measure 12 inches from the end touching the rafter along the level.
At that 12-inch mark, measure the vertical distance from the level up to the rafter.
That vertical measurement is your rise. If it measures 6 inches, your pitch is 6/12.
From a Ladder (At the Eave)
Safely place a ladder at the roof edge.
Hold a level horizontally against the roof surface.
Measure 12 inches along the level from the roof surface.
Measure from the end of the 12-inch mark straight down to the roof surface. That distance is your pitch rise per 12 inches of run.
Pitch Categories Explained
Low Slope (1/12 - 3/12)
Nearly-flat roofs common on commercial buildings and modern architecture. Require special materials like rolled roofing, BUR, or single-ply membranes. Standard asphalt shingles should not be used below 2/12. See our flat roof guide.
Conventional (4/12 - 9/12)
Most residential roofs fall in this range. Works with all standard roofing materials including asphalt shingles, metal, tile, and slate. The 5/12 to 7/12 range is the most common for suburban homes.
Steep (10/12 - 12/12)
Found on Victorian homes, A-frames, and certain architectural styles. Sheds water and snow efficiently but more expensive to install. Safety equipment mandatory.
Extreme (13/12+)
Rare in residential construction. Found on steeple roofs, mansard roofs, and decorative elements. Requires specialized installation techniques and additional fastening.
How Pitch Affects Material Selection
Your roof pitch directly determines which roofing materials you can use:
| Material | Minimum Pitch | Ideal Pitch Range |
|---|---|---|
| Built-up / flat roofing | 0.25/12 | 0.25/12 - 3/12 |
| Rolled roofing | 1/12 | 1/12 - 3/12 |
| Asphalt shingles | 2/12 | 4/12 - 12/12 |
| Metal panels | 3/12 | 3/12 - 12/12 |
| Clay / concrete tile | 4/12 | 4/12 - 12/12 |
| Wood shakes / shingles | 4/12 | 4/12 - 12/12 |
| Natural slate | 4/12 | 6/12 - 12/12 |
For a complete comparison of all roofing material types, see our roofing materials comparison guide.