Launch monitor metrics glossary
Last updated: June 20, 2026
By Andrew · Founder, Fore-ward Thinking — a golfer who lives in launch-monitor data and built an AI coach that remembers every session.
This glossary defines every number your launch monitor reports — what it measures and the unit — so you can read any shot with confidence. Metrics split into ball data (what the ball did) and club-delivery data (how the club arrived); not every monitor measures the delivery numbers. For what's good by club, see the per-club table in the GSPro data-analysis guide.
Ball data
Ball speed — How fast the ball leaves the clubface, in mph. The biggest single predictor of distance and the raw result of a good strike. A driver swung 100 mph at 1.50 smash produces 150 mph ball speed.
Club speed — How fast the head is moving just before impact, in mph. More speed raises distance potential, but only a centered strike converts it — which is what smash factor measures.
Launch angle — The vertical angle, in degrees, the ball leaves the face relative to the ground. It rises with the loft delivered at impact. Too low won't carry; too high balloons.
Launch direction — The horizontal angle the ball starts on, left or right of target. Under modern ball-flight understanding, the ball starts primarily where the face points at impact — so start line is mostly a face-angle story.
Backspin — The rate the ball spins backward, in rpm; creates height and stopping power and rises with loft. Driver ~2,000–3,000; 7-iron ~6,000–7,500; wedge ~9,000–11,500. Low iron spin usually signals a thin or de-lofted strike. (Source: Trackman.)
Side spin / spin axis — The sideways component of spin that curves the ball, usually shown as axis tilt. Right-tilt fades or slices for a right-hander; left draws or hooks. It's set by face angle relative to club path.
Spin rate — Total ball rotation, in rpm, combining backspin and side component. Most monitors report backspin and spin axis separately, which is more useful for diagnosing flight than a single total.
Carry vs total — Carry is air distance; total adds roll. On a simulator, carry is the honest number — total depends on the firmness GSPro models. Plan your gapping off carry.
Apex / peak height — The highest point of the shot, in feet or yards. Reflects launch and spin together; a healthy iron flight needs enough height to land softly.
Descent angle — How steeply the ball falls, in degrees. Steeper lands softer and stops faster — wedges land near 50°, a driver much shallower. Too flat an iron descent won't hold a green.
Club-delivery data
Measured directly only by some monitors — see which numbers your launch monitor can measure.
Smash factor — Ball speed divided by club speed; how efficiently energy transfers at impact. Club-dependent: driver tops near 1.50, 7-iron ~1.33, wedge ~1.24 (Trackman Tour averages). A high iron smash (1.40+ on a 7-iron) usually means a thin or de-lofted strike, not a better one. The full per-club table is in the
GSPro guide.
Club path — The horizontal direction the clubhead is moving at impact, in degrees relative to the target line. Positive is in-to-out (right of target, for a right-hander); negative is out-to-in. It's one half of what shapes the shot — where the club is going, not where the face points. (Source: Trackman.)
Face angle — Where the clubface points at impact relative to the target line, in degrees. The dominant factor in start line — the ball starts roughly where the face points — and one input to curve. (Source: Trackman.)
Face-to-path — The difference between face angle and club path at impact. The primary driver of curve: the ball curves away from the path, toward the face. Face open to the path fades or slices; closed draws or hooks; square flies straight. (Source: Trackman.)
Angle of attack — The up-or-down direction the clubhead moves at impact, in degrees. Irons are struck descending (negative) to compress the ball and take a divot in front; the driver is best struck level to slightly upward (positive) to add carry and lower spin. Not every monitor measures it. (Source: Trackman.)
Dynamic loft — The actual loft on the face at impact, which can differ from the club's stated loft. More dynamic loft raises launch and usually spin — which is why casting, flipping or scooping add launch and spin, never reduce them. (Source: Trackman.)
Dispersion — How scattered your shots are around their average, side-to-side and in distance. The truest measure of consistency: a tight group of slightly-off shots scores better than a wide spread of occasional perfect ones.
Quick reference
Frequently asked questions
What's the difference between club path and face angle?
Club path is the direction the clubhead travels at impact; face angle is where the face points. The face dominates the start line; the gap between face and path (face-to-path) curves the ball.
Why is low spin bad on an iron?
Iron backspin creates the steep descent that stops the ball on the green. Too little spin — often from a thin or de-lofted strike — gives a flat landing and less control. (The driver is the opposite: lower spin there usually adds distance.)
Which launch monitor metrics are measured vs estimated?
Ball data (ball speed, launch, spin, carry) is measured by virtually every monitor. Club-delivery data (club path, face angle, angle of attack) is measured directly only by camera/photometric units; radar and budget units often estimate or omit it.
Keep going: GSPro data analysis
(how to read these in practice, plus per-club norms) ·
the launch monitor practice plan ·
all guides.