Rafter Length Calculator
Calculate common rafter lengths based on run and pitch
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How to Use This Calculator
Run.
Pitch.
Overhang.
Get Length.
Understanding Rafter Length Calculations
Pythagorean theorem.
Birdsmouth cut.
Ridge board.
Tail.
Formula & Calculations
Sqrt(Run^2 + Rise^2)
Key Factors to Consider
Lumber size
Spacing
Span rating
Collar ties
Frequently Asked Questions
1Pitch 6/12?
Rise 6" per 12" run.