Enter the lead and mean diameter of a helix or screw into the calculator. The calculator will display the lead angle of the helix.

The following formula is used to calculate the lead angle of a helix or screw.

LA = arctan (L/PI*D)
• Where LA is the lead angle
• D is the mean diameter of the helix

To calculate a lead angle, take the lead divided by pi, then multiply by the diameter. Finally, take the arc tangent of this result.

A lead angle is defined as the angle between a thread and the plane of rotation the thread sits on. This can also be applied to helixes.

## How to calculate lead angle?

How to calculate a lead angle

1. First, measure the lead of the helix

The lead of the helix is the axial distance traveled during one complete turn along a helix or screw thread. Measure this is whichever is your preferred unit, just make sure the units are consistent.

2. Next, measure the mean diameter

This is the average diameter of the helix, usually taken through measure the total diameter and dividing by two.

3. Finally, calculate the lead angle

Enter the information from steps 1 and 2 into the equation above to calculate the lead angle.