What this calculator actually does
Roof pitch is a geometric slope. If rise and horizontal run use the same unit, their ratio determines pitch per 12, percent slope and the angle from horizontal. The slope factor is the hypotenuse ratio used to convert horizontal run into sloped length.
How to use this calculator
Measure or enter the vertical rise and horizontal run using the same unit.
Optionally enter a horizontal run length when you also need the sloped geometric length.
Review pitch per 12, angle, percent slope and factor as equivalent ways to express the same geometry.
Where people use it
- •Checking drawing or field slope measurements
- •Converting pitch notation to degrees
- •Early roofing geometry and sloped-length checks
Example: 6 rise over 12 run
6 ÷ 12 = 0.5, so the roof is 6:12, has a 50% slope and an angle of about 26.565°.
Assumptions and limits
- •This calculator describes geometry only. It does not approve a roof design, material, load path or construction method.
- •Field measurements can be affected by uneven surfaces and existing finishes; verify critical dimensions independently.
Frequently asked questions
What does a 6/12 roof pitch mean?+
The roof rises 6 units vertically for every 12 units of horizontal run.
How is roof angle calculated?+
The angle from horizontal is the arctangent of rise divided by run.
Is pitch the same as percent slope?+
They describe the same geometry differently. Pitch per 12 scales the rise to a 12-unit run, while percent slope multiplies rise/run by 100.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
Scale Calculator — Drawings, Maps and Models
Convert real measurements to scaled drawing or model sizes, convert scaled sizes back to real dimensions, or find the 1:N scale ratio.
OpenFeet and Inches Calculator
Add, subtract, multiply, divide or convert feet and inches, including decimal and fractional inch inputs, with decimal feet and metric equivalents.
OpenSquare Footage Calculator
Calculate square footage for rectangles, circles and triangles, convert the area to square meters and estimate cost from a price per square foot.
OpenBoard Foot Calculator — Lumber Volume & Cost Basis
Calculate board feet from lumber thickness, width, length and quantity, then add an optional waste allowance for a project tally.
OpenConcrete Calculator — Slab and Cylinder Volume
Estimate concrete volume for a rectangular slab or cylindrical pour in cubic feet, cubic yards and cubic meters, with an optional waste allowance.
OpenGravel Calculator — Cubic Yards & Tons
Estimate gravel volume from length, width and depth, add a project allowance and convert cubic yards to tons using a density you can verify with the supplier.
OpenBrick Calculator — Bricks, Mortar, Cement, Sand & Cost
Estimate bricks for one or more walls after opening deductions, then calculate wet and dry mortar, cement bags, sand volume and optional material cost from actual brick dimensions and mortar-joint inputs.
OpenConcrete Block Calculator — CMU Blocks, Mortar, Grout, Pallets & Cost
Estimate concrete blocks for a wall after opening deductions, then plan mortar bags, pallets and optional core-fill grout from actual block-face dimensions and editable product coverage, void fraction and bag-yield inputs.
OpenMore in this calculator collection
Browse nearby calculators in the same topic cluster so related pages reinforce each other instead of sitting as isolated URLs.
Free publisher widget
Put this calculator on your website
Give readers the live calculator without rebuilding the math. Copy the responsive embed in one click, or customize width, height, border and corner radius before publishing. The branded MAXScanner attribution stays visible.
Keep the result connected to the real job
MAXScanner keeps the formula and assumptions beside the result so you can verify the number before using it in a drawing, estimate, specification, worksheet or document. Where a supplier, manufacturer, drawing or applicable standard owns a requirement, that source remains authoritative.