What does x:12 roof pitch mean?

An x:12 pitch states how much the roof rises for every 12 horizontal units of run. A 6:12 roof rises 6 units for each 12 units of run, which is the same geometry no matter which measurement unit you use.

What is the difference between wall-line rafter length and total rafter length?

Wall-line rafter length covers the main right triangle from the wall line to the high point. Total rafter length adds the overhang tail along the same slope so you can estimate a fuller stock length.

How is overhang handled here?

The overhang input is treated as a horizontal projection beyond the wall line. The calculator then converts that projection into extra sloped tail length before adding it to the total rafter length.

Will the three input modes agree on the same roof?

Yes. Rise + run, angle + run, and pitch + run all resolve to the same roof geometry when they describe the same slope. The calculator simply starts from a different known input and derives the rest.

Is this a structural or code-compliance check?

No. This is a geometry estimator for roof shape, slope, and rafter length. It does not judge spans, loads, fastening, material suitability, or code approval.

Roof Pitch Calculator

Plan a roof side profile from rise and run, roof angle and run, or x:12 pitch and run. Get the matching roof angle, slope percent, roof ratio, and rafter lengths before you cut stock or compare roof options.

Units

Input Mode

Active roof equation

Run

Rise

Overhang