Spin Index
A normalized percentage comparing your actual spin rate to the expected optimal spin rate.
Full Definition
Spin Index is a TrackMan metric introduced in 2025 that expresses your spin rate as a percentage of the expected optimal spin for your specific launch conditions. A Spin Index of 100% means your spin is exactly what physics predicts as optimal for your club speed, attack angle, and dynamic loft. Values above 100% indicate more spin than expected; below 100% indicates less. This normalizes spin across clubs and swing speeds, making it easier to compare spin efficiency.
Formula
Optimal RangeGeneral guidance based on tour averages. Your optimal range depends on swing speed, physical attributes, and individual technique. Many golfers succeed with metrics outside these ranges.
85-110% across all clubs
Why It Matters
Raw spin numbers vary dramatically by club (2,500 RPM for driver vs 10,000 RPM for wedges), making it hard to know if your spin is good or bad. Spin Index normalizes this so you can quickly tell if your spin is optimal regardless of club. Consistently low Spin Index may indicate a strike or equipment issue.
Related Terms
Spin Rate
How fast the ball rotates around its axis, measured in revolutions per minute (RPM).
Spin Loft
The difference between dynamic loft and attack angle, which determines spin rate.
Dynamic Loft
The actual loft of the clubface at impact, which differs from the club's stated loft.
Attack Angle
The vertical direction the clubhead is moving at impact—up, down, or level.