Conforming equipment: the rules, the lists and the limits in one place.

Which rules apply

The playing rules are in Rule 4 of the 2023 Rules of Golf, in effect from 1 January 2023. The R&A says the next edition is due on 1 January 2028. The technical specifications are in the separate joint Equipment Rules. The copy hosted by the Japan Golf Association is labelled version 1.3; we could not confirm its effective date from a primary source.

Clubs: Rule 4.1a

Conforming when new, and after changes

Under Rule 4.1a(1), a club used to make a stroke must conform both when new and after any change, deliberate or accidental. Wear from normal use does not make a conforming club non-conforming, and a club that did not conform when new cannot become conforming through wear. Making a stroke with a non-conforming club means disqualification. Merely carrying one is not penalised, though it still counts towards the 14-club limit in Rule 4.1b.

Clubs damaged during a round: two R&A pages disagree

The current Rules of Golf text of Rule 4.1a(2) on randa.org says that if a conforming club is damaged during the round, the player may repair it or replace it with another club, except where the damage came from abuse. The damaged club is treated as conforming for the rest of the round. A replacement must follow Rule 4.1b(4): no borrowing from anyone playing on the course and no building a club from parts carried by anyone on the course. The damaged club must be taken out of play before the next stroke.

The R&A's online Equipment Rules, Part 1, still summarises the earlier position, that a player normally may not replace a club damaged during a round. The two pages therefore disagree. The Rules of Golf text is the one in force, so we follow Rule 4.1a(2).

A Committee can narrow the replacement right. Model Local Rule G-9, updated on 1 January 2026, lets a Committee (typically not at club level) restrict replacement to clubs that are broken or significantly damaged, with the replacement filling the gap in the set; the R&A's example is that a broken 5-iron may not be replaced with an extra driver. The 2026 update lets players repair a damaged club with components carried in their own bag or carried for them by someone else on the course. G-9 applies only when a Committee adopts it.

No mid-round changes to performance

Rule 4.1a(3) forbids a stroke with a club whose performance was deliberately changed during the round, by an adjustable feature, a physical change or a substance on the head. Putting an adjusted feature back before the stroke avoids the penalty. Material to protect or clean the face is generally allowed, but not to influence how the ball moves, and tape on the face is not allowed for any purpose.

Balls: Rule 4.2

Rule 4.2a requires every stroke to be made with a conforming ball, and forbids playing a ball whose performance was deliberately changed, for example by scuffing, heating or a substance other than for cleaning; the penalty is disqualification. Rule 4.2b deals with a ball that breaks into pieces (no penalty, replay the stroke), and Rule 4.2c with a ball cut or cracked during the hole. Details are on the golf balls page.

Key limits in the Equipment Rules

The conforming lists

• List of Conforming Driver Heads. Part 2 says it is updated weekly. Model Local Rule G-1 lets a Committee require every driver to have a listed head, with disqualification for a stroke with an unlisted driver and no penalty for carrying one. Heads made before 1999 are exempt. It is recommended only for elite and professional events.
• List of Conforming Golf Balls. Balls submitted within the last 12 months and ruled to conform, updated on the first Wednesday of each month. Model Local Rule G-3 requires a listed ball, with disqualification as the penalty. The R&A recommends it for professional and top amateur competitions, and other events may use it at the Committee's discretion. G-4, the one ball rule, requires a single brand and model for the round and is recommended only for competitions of highly skilled players.
• Equipment database. The R&A also runs a searchable database for checking whether a ball or club conforms.

G-1, G-3 and G-4 apply only when a Committee adopts them. Without G-3, Part 3 says a ball is presumed conforming unless there is strong evidence otherwise.

Grooves: the 2010 rule and its phase-in

• 1 January 2010. Tighter groove and punch-mark specifications took effect for new club models, other than drivers and putters, made on or after that date, and for clubs whose face markings are purposely altered, for example by re-grooving.
• Model Local Rule G-2. A Committee may require clubs to meet the 2010 specifications. G-2 applies only when a Committee adopts it, and is recommended only for competitions of highly skilled players. Golfers not competing at elite level could keep using clubs that conformed to the 2009 rules until at least 1 January 2024.
• 25 January 2024. The R&A said that, after review, the 2010 specifications would stay in effect only through G-2. Any future decision to apply them to all golfers would not take effect until at least four years after it is announced.

The specifications themselves are on the wedges page. The R&A publishes Supplementary Paper B (field measurement of pre-2010 grooves) and Supplementary Paper C (2010 face markings) with its online Equipment Rules.

Length: Model Local Rule G-10

On 12 October 2021 the R&A and USGA announced Model Local Rule G-10, available from 1 January 2022. It lets a Committee limit clubs other than putters to 46 inches, measured as in the Equipment Rules, with a tolerance of 0.20 inches. It applies only when a Committee adopts it, and it is recommended only for competitions limited to highly skilled players, meaning professional and elite amateur events. The governing bodies said G-10 is not a Rule of Golf, so recreational golfers are not required to follow it.

Where G-10 is in force, a stroke with a longer club means disqualification, carrying one is not penalised, and the exception that would otherwise allow longer clubs for a physical need does not apply. The R&A traces G-10 to a 2014 Area of Interest notice on clubs longer than 48 inches, a 2016 proposal put on hold in 2017 when the Distance Insights project began, and a notice and comment reopened in February 2021.

Outside G-10, a Committee may allow longer clubs for a medical or physical need, and Part 7 lets a player who needs clubs longer than 48 inches use them with the Committee's authorisation if the shortest club (putter excluded) is no more than 10 inches shorter than the longest. See players with disabilities.