Distance-measuring devices: what Rule 4.3 allows.

The default since 2019

The USGA's guide "Understanding the Rules of DMDs", updated for 2023, says distance-measuring devices have been allowed under the Rules of Golf since 1 January 2019, provided the player does not access prohibited information. That reversed the earlier position. From January 2006 the R&A and USGA allowed these devices only where a Committee adopted a Local Rule, and a 2009 statement said such devices had to measure distance only, not wind, slope or temperature.

The USGA guide names laser rangefinders, handheld GPS units and GPS watches as common stand-alone devices, and mobile phones and tablets as multi-function devices.

What Rule 4.3a allows and forbids

Rule 4.3 governs how equipment is used during a round. Whether clubs and balls conform is a separate matter under Rules 4.1 and 4.2.

The USGA guide calls slope-adjusted or other "plays like" figures "effective" playing distances, and lists them among the information a player may not access.

Devices with extra functions

Some rangefinders and watches can do more than the rules allow. The USGA guide says a device that can perform a prohibited function may be used, as long as that function is not accessed during the round. It adds a catch for devices you can see without trying: if a readily viewable device, such as a multi-function watch, is displaying prohibited information, you are treated as having used it even if you did not look.

One maker, according to a retailer listing, sells rangefinders with a switch that turns the slope function off, and says the unit is legal for tournament play with slope disabled. That is the maker's claim. Under the rules, what matters is whether prohibited information is accessed or displayed during the round, so check your device's settings before you start.

Penalties: two descriptions

The Rules of Golf say a first breach of Rule 4.3 brings the general penalty (two strokes in stroke play, loss of hole in match play), applied to the next hole if the breach happens between holes. A second breach means disqualification, but only if an intervening event happened after the first breach.

The USGA's DMD guide describes the first breach the same way and a second breach in the same round as disqualification, without mentioning the intervening-event condition. The Rules of Golf text is the one that governs.

When a Committee bans them: Model Local Rule G-5

Rule 4.3 lets a Committee restrict distance-measuring devices by Local Rule. Model Local Rule G-5 is the version a Committee may adopt to prohibit them during a round, with breaches penalised under Rule 4.3. It applies only when a Committee adopts it, so check the Terms of the Competition before an event.

The professional tours

On 15 April 2025 the PGA Tour announced that devices would be allowed at six PGA Tour events over four weeks that spring, from the RBC Heritage and Corales Puntacana Championship (17 to 20 April) to the Truist Championship and ONEflight Myrtle Beach Classic (8 to 11 May), as a pace-of-play test. The Korn Ferry Tour tested them at three events, having earlier tested them at four events in 2017. The same release said PGA Tour Americas and PGA Tour Champions already allowed devices in competition, and that devices had to measure distance only, with course mapping, club advice and slope, elevation and wind functions turned off. We could not confirm the PGA Tour's policy for 2026 from a tour source.

Launch monitors

Launch monitors measure club and ball data. Golf.com explains that Doppler radar units track the whole flight from behind the golfer, while camera units record impact and the first few feet of flight from the side and calculate the rest. They are practice and fitting tools: during a round, Rule 4.3a does not allow equipment that analyses your swing or uses data from the current round.

Other equipment under Rule 4.3

• Audio and video. Listening to or watching content unrelated to the competition is allowed, but not using audio to block out distractions or keep swing tempo. Model Local Rule G-8 lets a Committee ban audio and video devices during a round, only when it adopts that rule.
• Training aids. General stretching equipment is allowed (not during a practice swing), but golf training or swing aids, such as alignment devices, are not.
• Medical equipment. Rule 4.3b allows equipment used for a medical reason if the Committee decides it gives no unfair advantage.

Nothing on this page says a particular device is allowed in competition. Read the Terms of the Competition, and turn off any function the rules forbid before your round starts.