Rafter length calculator
Estimate sloped rafter and overhang lengths from a roof run and pitch.
What you enter
- Horizontal run (in)
- Hold the slope by
- Pitch rise (in / 12)
- Pitch run (in)
- Roof angle (deg)
- Height from wall to ridge (in)
- Overhang (in)
Main results
- Rafter length
- Roof angle
- Overhang length
What it follows
Plain geometry on the run, slope and overhang you type; no building-code table is looked up.
Every result is marked REVIEW REQUIRED. Illustrative project-planning values only; jurisdiction, species, grade, loads, wet service and current adopted tables require review. Do not use a result directly for permit, purchase, or field use.
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The calculator opens inside the designer, after you sign in.
Accounts are issued by the DeckAndShed team. There is no self-service sign-up.