In the appropriate fields of the calculator, decide whether you want to include the cost of installation in the calculations. Our tool can also figure out the approximate roof truss cost. Input the roof length, the on-center spacing (the distance between the middles of two neighboring roof trusses), and the rafter calculator will return the number of roof trusses needed. You can input the roof pitch in whichever format you prefer (angle, percentage, ratio), and our tool will automatically tell you the other ones. You can input any of the two values to get the third one calculated. Here as well, our calculator works both ways. After doing that, you will see the rafter length in the bottom-most field.
If you decided to include roof pitch in your calculations, you will need to input the run and the pitch of the roof to get the rafter length.
