Smash Factor

The ratio of ball speed to club head speed at impact, calculated by dividing ball speed by club speed. A smash factor of 1.50 means the ball is leaving the club face at 1.5 times the speed the club was traveling.

Smash factor is a measure of contact efficiency: perfect center-face contact with no off-axis hit produces the maximum smash factor for a given club. The theoretical maximum for a driver is approximately 1.50 (limited by the rules of golf for legal driver faces); typical amateur smash factor with a driver is 1.42–1.48.

A consistently low smash factor (below 1.40 for driver) indicates off-center contact and is one of the clearest signals that ball-striking is hurting distance.