Rafter Length Calculator
Rafter length from rise and run.
Amortization schedule
| # | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
Showing first 12 of months.
Growth over time
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Introduction
Rafter Length Calculator — Rafter length from rise and run. Enter Rise (ft), Run (ft) to get an instant, accurate result.
Formula
Rafter length = √(rise² + run²), the exact Pythagorean theorem applied to the right triangle formed by a roof's rise and run.
Step-by-step
- Enter the Rise (ft).
- Enter the Run (ft).
- Click Calculate to see your result instantly.
Real-world example
Example: With Rise (ft) = 6, Run (ft) = 12, the Rafter Length Calculator gives Rafter Length Ft: 13.4164.
Frequently Asked Questions
Does this include the overhang?
No, this calculates the rafter length from ridge to wall plate based on rise and run only — add overhang length separately if needed.
Why use the Pythagorean theorem here?
A sloped rafter is the hypotenuse of a right triangle where the two legs are the vertical rise and horizontal run, so √(rise² + run²) gives its exact length.
What inputs does the Rafter Length Calculator need?
You'll need to provide: Rise (ft), Run (ft). All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Rafter Length Calculator?
The Rafter Length Calculator applies the formula exactly as calculated — Rafter length = √(rise² + run²), the exact Pythagorean theorem applied to the right triangle formed by a roof's rise and run. — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Rafter Length Calculator free to use?
Yes, the Rafter Length Calculator is completely free, requires no signup, and runs instantly in your browser.
About the Rafter Length Calculator
The Rafter Length Calculator uses a real, verifiable formula — Rafter length = √(rise² + run²), the exact Pythagorean theorem applied to the right triangle formed by a roof's rise and run. — so results are accurate every time, not an approximation.