Roof Pitch Calculator
Convert roof rise and run into pitch, slope percentage, angle, rafter length, roof area, rafter quantity and stock-material cost.
Default project preview
6 in 12
Rafter length
14.53 ft
Slope factor
1.118
Rafter positions
24
Installed rafters
48
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Pitch per 12 = rise ÷ run × 12. Angle = arctangent(rise ÷ run). Rafter length = √(run² + rise²) plus the sloped overhang.
BuildMeter Guides
Understand the measurements and assumptions
Use these visible reference guides before changing project inputs or planning allowances.
FAQ
Roof Pitch Calculator questions
What does a 6-in-12 roof pitch mean?+
The roof rises 6 units for every 12 equal units of horizontal run.
Is rafter length the same as roof run?+
No. Rafter length follows the slope and is therefore longer than the horizontal run.
Does this size rafters structurally?+
No. Rafter size depends on span, spacing, loads, species, grade and building code.