Rafter Length Calculator
Result
Rafter Length (no overhang)5.52 m
Rafter Length (with overhang)5.82 m
Ridge Board Height2.33 m
Half Span (run)5 m
↗ Construction
Rafter Length Calculator — free online calculator.
Formula
Rafter = (Span/2) / cos(Pitch); RidgeHeight = (Span/2) × tan(Pitch)
- Rafter Length Calculator calculates its result from Span, Pitch. It uses the formula Rafter = (Span/2) / cos(Pitch); RidgeHeight = (Span/2) × tan(Pitch). Change any input to recalculate the result instantly.
- The main inputs are Roof Span, Pitch Angle, Eave Overhang. Enter them in the units and format shown in the calculator.
- Keep measurements and project assumptions consistent before comparing or combining values.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Rafter Length
Inputs
- Roof Span: 10 total width
- Pitch Angle: 25
- Eave Overhang: 0.3
Using Span = 2, Pitch = 3, the calculated result is -0.1425465431.
Sample result: Calculating…
Frequently asked questions
What does the Rafter Length calculate?
Rafter Length Calculator — free online calculator.
Which values should I enter?
Enter Roof Span, Pitch Angle, Eave Overhang using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Rafter = (Span/2) / cos(Pitch); RidgeHeight = (Span/2) × tan(Pitch).
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.