#### Spin axis represents the amount of curvature of a golf shot

**A negative spin axis represents a ball curving to the left, a positive spin axis represents a ball curving to the right, and a zero spin axis represents a shot that has no curvature.**

Spin axis is determined at impact and should remain the same throughout the flight of the ball. Even though wind may “push” the ball in different directions, the spin axis will remain unchanged. Spin axis is measured relative to the horizon.

The spin axis can be associated to the wings of an airplane. If the wings of an airplane are parallel to the ground, this would represent a zero spin axis and the plane would fly straight. If the wings were banked/tilted to the left (right wing higher than left wing), this would represent a negative spin axis and the plane would bank/curve to the left. And the opposite holds true if the wings are banked/tilted to the right.

In general, a spin axis between -2 and 2 can be considered a straight shot. Under normal conditions, it would be difficult to see curvature on a shot with a spin axis between -2 and 2. The higher the number of the spin axis, the more curvature that should be visible.

**Technical Definition: **

Spin Axis – The tilt angle relative to the horizon of the golf ball’s resulting rotational axis immediately after separation from the club face (post impact).Remark: Positive angles refer to a ball curving to the right (negative refer to a ball curving to the left).

**Left-handed golfer**

- Large negative spin axis can be described as a slice
- Small negative spin axis can be described as a fade
- Small positive spin axis can be described as a draw
- Large positive spin axis can be described as a hook

**Right-handed golfer**

- Large negative spin axis can be described as a hook
- Small negative spin axis can be described as a draw
- Small positive spin axis can be described as a fade
- Large positive spin axis can be described as a slice

#### Indoor vs Outdoor Mode

Note: When using TrackMan in “outdoor” mode, the first ~30 yards of ball flight are used to determine the spin axis value. However, since the spin axis does not change during the ball flight, this measurement is considered to be made after separation from the club face.

When using TrackMan in “indoor” mode, the club delivery measurements (spin loft and face to path) are used to calculate the spin axis.

#### Spin Axis Examples

**Optimized 150 Yard Shot**

- -2 spin axis ≈ 2.2 yards of left curvature
- -10 spin axis ≈ 11 yards of left curvature
- 2 spin axis ≈ 2.2 yards of right curvature
- 10 spin axis ≈ 11 yards of right curvature

**Optimized 200 Yard Shot**

- -2 spin axis ≈ -3 yards of left curvature
- -10 spin axis ≈ -15 yards of left curvature
- 2 spin axis ≈ 3 yards of right curvature
- 10 spin axis ≈ 15 yards of right curvature

The standard assumption for spin axis is zero for all clubs. It is a standard assumption that the ball has no curvature (zero spin axis).

#### Read what our TrackMan University Masters say about Spin Axis…

**Mark Anderson**

**Philadelphia Cricket Club, PA, US**

*“I use spin axis in conjunction with face angle and club path to determine where the student is hitting the ball on the face of the club. If the face to path number is positive and spin axis is negative, I know that the student hit the ball towards the toe side of the center of gravity of the club head.”*

**Ryan Johnson**

**Carl’s Golfland, MI, US**

*“Spin axis allows me to see what type of shot shape someone typically plays. Spin axis determines if the ball is drawing by a negative number and fading by a positive number. I can see if their natural shot is what I would consider playable. I consider a single digit spin axis value to be a playable ball flight.”*

**Hugh Marr**

**Premium Golf Consulting, UK**

*“Spin axis is a great measure for centeredness of contact when used in conjunction with face to path. Spin axis gives the coach great feedback to a player’s striking tendencies.”*

Could you please tell me how to calculate spin axis from backspin and sidespin.