Smash factor: what it tells you

What is smash factor?

It's ball speed divided by clubhead speed. That's the whole recipe. Trackman says the result relates to how much energy moves from the club head to the ball.¹

Bushnell gives it a second name, efficiency, and describes it as the ratio between club head and ball velocities.²

A quick example from Trackman. With a club speed of 100 mph, a smash factor of 1.50 means a ball speed of 150 mph.¹

If you're new to the two speeds themselves, start with ball speed and clubhead speed.

What's a normal range?

It depends on the club. Trackman says a golfer would hope for a smash factor near 1.50 with the driver. A pitching wedge should be near 1.25. The more loft on the club, the lower the expected number.¹

Here are Trackman's averages for a few groups.

Notice that even the tour driver averages sit just under 1.50.¹

Does a small difference in smash factor matter?

It can. Trackman compares two golfers who both swing a driver at 100 mph. One has a smash factor of 1.40, so the ball leaves at 140 mph. The other has 1.50 and a ball speed of 150 mph. That 10 mph gap equates to roughly 20 yards.¹

Same swing speed. Very different result.

Why does my smash factor drop with a wedge?

Loft. Trackman says the higher the loft, the lower the smash factor to expect.¹

There's a second link through something called spin loft. That's the angle between the way the club head is moving and the way the face is pointing. Trackman says a higher spin loft goes with a lower smash factor, when nothing else changes.³ You can read how it's built from two other numbers on the attack angle and loft page.

So compare each club with itself, or with the figure for that club. Don't compare your wedge with your driver.

Is a low number always a bad strike?

Not always, but contact is one thing to check. Strikes toward the toe or heel can cut potential ball speed.⁴ A lower ball speed with the same club speed means a lower ratio.¹

Other things can pull the number down too, such as the loft you're delivering at impact.³

How do I use it in practice?

Pick one club. Hit a set of shots. Watch whether the number moves up or down as your contact changes. The ratio is the same maths every time: ball speed over club speed. So if you know any two of the three numbers, you can work out the third.¹

For the next step, look at launch angle and spin rate to see what the ball does once it has that speed.