Attack angle and dynamic loft

What is attack angle?

It's whether the club head is moving up or down as it meets the ball, and by how much. Trackman measures it against the horizon at the moment of maximum compression.¹

Bushnell puts the sign in plain terms. A positive number is hitting up on the ball. A negative number is hitting down on it.²

Should the number be negative or positive?

It depends on the club and the lie. Trackman says shots hit off the ground, not off a tee, should have a negative attack angle to optimize trajectory.¹

With the driver, the advice flips. Trackman calls hitting up on the ball a must for maximum distance. It adds that a positive attack angle doesn't settle the matter alone, because club fit plays a part.¹

Golfers with slower club speeds get a warning. Hitting too far down with irons can hurt distance and control on approach shots.¹

Here are Trackman's attack angle averages.

What is dynamic loft?

It's the amount of loft on the club face at the moment of impact. Trackman measures it against the horizon.³

Several things change it. Trackman lists attack angle and how the shaft bends. It also lists how you release the club head, whether the face is open or closed to the path, and where the ball hits the face.³

Why does dynamic loft matter?

Loft decides a lot about the shot. Too much can send the ball too high and cost distance. Too little can send it too low, so it rolls out a long way and the distance is hard to judge.³

It also feeds the launch angle. Trackman says launch angle is always a little less than dynamic loft, though the two are similar.⁴ What the ball does after launch is covered under spin rate and launch.

Here are Trackman's dynamic loft averages.

How do the two combine?

Spin loft sets the head's travel direction against the face's orientation. Subtracting attack angle from dynamic loft gives a close estimate of it.⁵

That estimate drifts when the face and path don't match. The bigger the face-to-path gap, the more it drifts.⁵

Why care? With all else equal, a higher spin loft gives a higher spin rate.⁵ It also lowers smash factor, which the smash factor page covers.⁵

What should I look at first?

Look at attack angle and dynamic loft together, since each one changes what the other means. If a shot flies too high or too low, check dynamic loft. If the spin looks off, check the pair that makes spin loft.⁵