A rafter calculator is a construction calculator that is pre-programmed with Pythagorean formulas. These calculators help builders determine the length of rafters for use in construction projects.
There are also smart phone construction calculator apps available that function the same as a rafter calculator. By plugging in the known information, such as the pitch and run of a roof, the calculator predicts the length and angle of rafters to be cut. The rafter calculator essentially takes the place of the framing square and roofing charts. The use of the calculator can reduce human error and help streamline the construction project.