Roof Truss Pitch & Angle Calculator
Roof pitch, roof angle, rise, and run are all different ways of describing the same slope. This roof truss pitch calculator converts your chosen pitch (like 6/12) into a precise angle in degrees, along with rise and run in feet or meters.
Calculate Your Roof Pitch & Angle
Enter your building specifications below. Results and the roof diagram update live as you type.
Live Roof Diagram
Results
Estimate Your Project Budget
Automatically calculated from your inputs above in the calculator.
Estimates only. Actual costs vary by region, supplier, and site conditions.
Pitch, Angle, Rise, and Run Explained
Roof pitch is expressed as inches of rise per 12 inches of horizontal run — a 6/12 pitch rises 6 inches for every foot it runs, which works out to a roof angle of 26.57°. Steeper pitches shed snow and water faster but use more rafter length and roofing material per square foot of footprint.
Rise is the vertical distance from the wall plate to the ridge; run is the horizontal distance from the outside wall to the center of the building (half the span). Rafter length is then found with the Pythagorean theorem from rise and run — see the formulas below.
Most residential roofs fall between 4/12 and 9/12, balancing drainage, material cost, attic headroom, and wind exposure. Enter any pitch from 2/12 to 12/12 above to see the exact angle, rise, and rafter length for your design.
The Math Behind the Calculator
Roof Pitch Angle
The pitch angle is the angle between the rafter and a horizontal line, derived from the rise-to-run ratio.
Rise
Vertical distance the roof climbs from the wall plate to the ridge.
Rafter Length
The Pythagorean theorem gives the true sloped length of the rafter.
Roof Area
Footprint area is divided by the cosine of the pitch angle to account for slope.
Truss Count
Number of trusses required based on on-center spacing.
Total Load
Combined dead and live loads multiplied across the total roof area.
Frequently Asked Questions
Roof truss degree calculator
Enter a pitch (rise per 12" of run) above and the calculator converts it to an exact roof angle in degrees using the arctangent of rise over run.
Roof truss rise calculator
Rise is your run (half the span) multiplied by pitch divided by 12 — shown live in the results panel as you change span or pitch.
Truss length calculator
The Pitch & Angle and Rafter Length tools return exact member lengths.