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

## Lead Angle Formula

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
- L is the lead
- D is the mean diameter of the helix

How to calculate a lead angle

**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 units, just make sure the units are consistent.

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

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

## FAQ

**What is a lead angle?**

A lead angle is defined as the angle between the helix or thread and the plane of rotation. The plane of rotation is most often considered as the axial plane.

**What is a thread?**

A thread is a type of physical structure used to hold screws in place when assembled. It’s a helical type structure that revolves around a cylinder and moves down along the axial length.