Two researchers have analyzed why golf balls lip out. Their study shows it’s more physics than bad luck.
Golf has long been known to involve a great deal of physics. Many phenomena on the course are often accepted as bad luck, though they often have scientific explanations. As British mathematician John Edensor Littlewood noted in 1986, “Golfers are not as unlucky as they think.”
The Science Behind the Lip-Out
In a recent study published in the journal Royal Society Open Science, Stephen John Hogan from the University of Bristol and Máté Antali from Széchenyi István University in Hungary examined the physics behind the infamous “lip-out.” Every golfer knows the moment: a well-aimed putt rolls toward the hole, hits the edge at the wrong angle, and instead of dropping in, it spins around or bounces out—forcing another stroke.
The study, titled “Mechanics of the golf lip out,” delves into the math and mechanics behind this frustrating event. The authors note that putting accounts for 40–45% of all golf strokes. As golf writer Peter Dobereiner once said, “Golf is half fun, the other half is putting.” South African pro Bobby Locke put it even more bluntly: “Drive for show, putt for dough.”
Two Types of Lip-Outs
Hogan and Antali identify two main types of lip-outs. The first is the “rim-lip-out,” where the ball rolls along the edge of the hole without dropping in. In this case, the ball’s center of mass stays above the green level. Even if it tilts slightly due to its initial speed, it lacks the momentum to fall into the hole. The researchers describe special equilibrium states where the ball rotates on the edge—nicknamed “golf balls of death.” A small disturbance can send the ball either into the hole or back onto the green. If the ball has no spin, it either lips out or drops in directly.
The second type is the “hole-lip-out.” This occurs when the ball has spin and enters the hole but rolls along the inner wall without touching the bottom. The ball’s potential energy converts to rotational energy and back, keeping it in motion until it exits the hole and rolls back onto the green. This scenario requires very specific initial conditions and is rare.
Beyond the Basics: Ballistic Lip-Outs
The researchers also mention a third type, the “ballistic-lip-out,” though they did not analyze it in detail. In this case, the ball hits the far edge of the hole, bounces to the opposite edge, and then rolls along the rim. It may eventually fall in or return to the green. Modeling this behavior would require precise data on impact timing and ball response—making it a complex challenge for future studies.