Two researchers analyzed why golf balls lip out. Their study shows there’s more physics than bad luck behind missed putts.
Golf is a game deeply influenced by physics, yet many of its quirks are often accepted without question. A new study by Stephen John Hogan of the University of Bristol and Máté Antali of Széchenyi István University in Hungary dives into one of golf’s most frustrating phenomena: the lip out. Their findings suggest that missed putts may be less about misfortune and more about mechanics.
The science behind the lip out
In their paper titled “Mechanics of the golf lip out”, published in the journal Royal Society Open Science, the researchers explore the physical and mathematical dynamics of lip outs. They note that putting accounts for 40–45% of all golf strokes, quoting golf writer Peter Dobereiner: “Golf is half fun, the other half is putting.” South African pro Bobby Locke famously said, “Drive for show, putt for dough.”
Every golfer has experienced it: the ball rolls toward the hole, hits the edge at the wrong angle, and instead of dropping, it circles the rim or bounces out. Hogan and Antali identify two main types of lip outs based on their mechanics.
Types of lip outs explained
The first is the rim-lip-out. This occurs when the ball rolls along the edge of the hole but doesn’t fall in. The ball’s center of mass remains above the green level, and even with some tilt from its initial speed, it lacks the momentum to drop. The researchers describe a balance state where the ball rotates along the edge—nicknamed “death balls.” A slight disturbance can send it either into the hole or back onto the green. If the ball has no spin, it either lips out or sinks cleanly.
The second type is the hole-lip-out. Here, the ball enters the hole but rolls along the inner wall with a spin misaligned with its roll direction. Its potential energy converts to rotational energy and back, without touching the hole’s bottom. Eventually, it climbs back up and exits the hole. This rare behavior only occurs under very specific initial conditions.
The authors also mention a third, more complex type: ballistic-lip-outs. In this case, the ball hits the far edge, bounces back and forth, and may either fall in or roll out. Modeling this precisely would require detailed analysis of impact timing and ball response—something beyond the study’s scope.
So next time your putt lips out, remember: it might not be bad luck—it could be physics at play.