Rafter Length Calculator

Calculate precise rafter lengths for your roof project with our free calculator. Input your measurements below to get accurate results.

Understanding Rafter Length Calculations

What is a Rafter?

A rafter is a structural beam that extends from the ridge or hip of a roof to its eave. It's one of the main components that provides support for the roof deck and covering materials.

How to Use This Calculator

  1. Enter the building width in feet
  2. Input the overhang length in inches
  3. Specify the beam width in inches
  4. Select the roof pitch (ratio over 12)