Roofing Giant · Free tool
Roof pitch is the rise in inches for every 12 inches of horizontal run. Enter the rise you measured, or pick a typical value, and the calculator returns the angle, the pitch multiplier and, with your footprint, the total roof surface and the squares of shingles to order.
Tool context: roof pitch affects measured surface area, access and installation scope. Continue with the roof replacement cost calculator, roof system anatomy, or all Roofing Giant tools.
How to measure pitch safely
From the attic
Hold a 12-inch level flat against the underside of a rafter, level it, then measure straight down from the 12-inch mark to the rafter. That vertical distance is the rise.
From a ladder at the eave
Rest the level on the shingles with the end at the edge, level it, and measure down from the 12-inch mark to the roof surface.
From the ground
Not precise, but a smartphone level app held to a gable line, or a photo compared with the table below, gets you close enough for planning.
Common pitches
| Pitch | Angle | Multiplier | Notes |
|---|---|---|---|
| 3/12 | 14.0° | 1.031 | Minimum for standard shingles; low-slope underlayment rules apply below 4/12 |
| 4/12 | 18.4° | 1.054 | Common on ranch homes |
| 6/12 | 26.6° | 1.118 | The most common DFW pitch; walkable |
| 8/12 | 33.7° | 1.202 | Steep for crews; harness required |
| 9/12 | 36.9° | 1.250 | Steep-pitch labor adders usually start here |
| 12/12 | 45.0° | 1.414 | Very steep; staging and roof jacks required |
Explore every part of your roof
Click or tap the roof itself to explore each component.
Rafters and roof decking
The structural base beneath every roof layer
What it does
Rafters support the roof. Plywood or OSB decking provides the surface that the roofing layers are attached to.
Why the detail matters
Soft, rotten or delaminated decking needs attention before new roofing is installed.
Rafters and roof decking
The structural base beneath every roof layer
What it does
Rafters support the roof. Plywood or OSB decking provides the surface that the roofing layers are attached to.
Why the detail matters
Soft, rotten or delaminated decking needs attention before new roofing is installed.
Component 2 of 10Ice & water barrier
At eaves, valleys and roof penetrations
What it does
This self-adhering membrane adds protection where water tends to collect. It sits beneath the shingles and seals around fasteners.
Why the detail matters
Coverage at vulnerable areas matters. Missing or damaged membrane leaves those details less protected.
Component 3 of 10Synthetic underlayment
Across the roof deck, beneath the shingles
What it does
Underlayment is a secondary water-shedding layer between the decking and the roof covering.
Why the detail matters
Tears, gaps and poorly lapped seams can interrupt this layer of protection.
Component 4 of 10Starter strip + architectural shingles
Along the eaves and rakes, then across the roof slopes
What it does
The starter course helps secure the first row. Architectural shingles overlap to form the main roof covering and shed rain down the slope.
Why the detail matters
Correct fastening and sealed shingle edges help the covering resist wind. Lifted or missing shingles deserve a closer look.
Component 5 of 10Ridge vent and ridge cap
At the highest point of the roof
What it does
The ridge vent provides an exhaust path from the attic. Cap shingles cover the ridge detail while preserving the vent opening.
Why the detail matters
Exhaust works with intake at the soffit (10). Both need a clear airflow path.
Component 6 of 10Step and counter flashing
Where a roof meets a wall or chimney
What it does
Flashing directs water away from roof-to-wall joints. Step flashing works with the shingle courses, while counter flashing protects the upper edge at a chimney.
Why the detail matters
Loose, missing or poorly fitted flashing can let water into these joints.
Component 7 of 10Pipe boot flashing
Around pipes that pass through the roof
What it does
The flashing base and fitted boot seal the joint where a vent pipe passes through the roof covering.
Why the detail matters
Cracked seals, loose boots and damaged flashing can become entry points for water.
Component 8 of 10Drip edge
Along the roof edges at the eaves and rakes
What it does
This metal edge directs runoff away from the fascia and toward the gutter at the eave.
Why the detail matters
Missing, bent or poorly positioned edges can let water run behind the gutter or onto the fascia.
Component 9 of 10Seamless gutter
Along the lower roof edge
What it does
Gutters collect runoff from the roof and guide it toward the downspouts, which carry water away from the home.
Why the detail matters
Debris, standing water, loose sections and leaking joints can interrupt drainage.
Component 10 of 10Vented soffit (intake)
Under the roof overhang
What it does
Soffit vents provide an intake path for outside air. That air moves through the attic toward exhaust vents near the ridge (5).
Why the detail matters
Insulation, paint or debris can block the intake openings and restrict airflow.
Feed the multiplier into the cost calculator, or skip the measuring and get a measured area from the instant estimate.
Get a clear next step for your roof.
Schedule a free, no-obligation inspection. You get photos, a written report and an honest recommendation: repair, replace, or leave it alone.