Curling (WCF) — Official Rules

Curling is a team sport played on a rectangular sheet of prepared ice. Two teams alternately slide polished granite stones toward a target of concentric circles called the house, the centre of which is the button. The object is, at the end of each segment of play (an end), to have more stones nearer the button than the opponent. A team's skip directs strategy; team-mates sweep the ice in front of a moving stone to influence its distance and curl. The team with the higher total score after all ends are completed wins the game.

Curling is governed worldwide by World Curling (the operating name adopted in the January 2024 brand refresh of the former World Curling Federation, WCF). These rules - The Rules of Curling and Rules of Competition (2025 edition) - apply to all World Curling championships and qualifying events, including the World Men's, Women's, Mixed Doubles and Wheelchair Curling Championships, and to the 2026 Olympic and Paralympic Winter Games (Milano Cortina) except where the IOC/IPC stipulate otherwise. National federations may adapt these rules for domestic play but international competition follows this edition.

Curling is played to a strict code of fair play and sportsmanship known as the Spirit of Curling. A true curler never seeks to win by breaking the rules or by intimidation; a player who breaks a rule should call it on themselves. Teams customarily shake hands before and after a game, and conceding when a game can no longer be won is an honoured tradition rather than surrender. Officials are present to ensure fairness, but the conduct of the players is expected to uphold the integrity of the game without their constant intervention.

Play takes place on a level ice sheet with a maximum length of 45.720 m (150 ft) and a maximum width of 5.000 m (16 ft 5 in) (commonly built about 4.75 m / 15 ft 7 in). A pebbled (sprayed) ice surface gives the stones their curl. The playing area runs between the two backboards/hacks at each end. Each sheet has a distinct colour-coded centre line and markings, and at major events the dimensions and ice conditions are verified by the chief ice technician before play.

At each end of the sheet is the house: four concentric circles centred on the tee (the exact centre point). The rings have diameters of 3.66 m (12 ft), 2.44 m (8 ft), 1.22 m (4 ft) and the central button (about 0.30 m / 12 in). A stone counts for scoring only if part of it lies within or touching the 12-foot circle. The closer a stone rests to the button, the better; the tee line passes through the centre of each house.

Key lines, measured along the sheet: the tee lines (through each button) are 34.75 m (114 ft) apart; the hog lines are 21.95 m (72 ft) apart, each set 6.40 m (21 ft) in front of its tee line; the back lines (rear edge of each house) are 38.40 m (126 ft) apart, each 1.83 m (6 ft) behind its tee line; and a centre line runs the length of the sheet. The hack (foot-hold) sits behind the back line, and hog-to-house the free guard zone is defined (see Chapter 4).

Each curling stone is made of dense polished granite with a handle. Including the handle and bolt, a stone must weigh a maximum of 19.96 kg (44 lb) and a minimum of 17.24 kg (38 lb), have a maximum circumference of 91.44 cm (36 in) and a minimum height of 11.43 cm (4.5 in). Each team uses a matched set of stones, and a player must deliver the same stone throughout the game (or its agreed replacement if a stone breaks). A stone that breaks in play is handled per the rules - generally the largest fragment is placed where it comes to rest, or the end is replayed.

Each player uses a brush (broom) for sweeping and balance. Following the 2015-16 'broomgate' controversy, World Curling strictly regulates brush-head fabric: only the single approved fabric/insert (the standard 'WCF/World Curling' yellow fabric) may be used in competition, and players on a team may share or swap brush heads only within the approved specification. For the 2025-26 season, World Curling updated its sweeping-equipment regulations (approved fabrics and brush-head construction); only equipment on the current approved list may be used. Footwear comprises a gripper and a low-friction slider sole for delivery.

A standard curling team consists of four (4) players, who may be supported by one alternate (fifth player) and a coach. The four playing positions, in throwing order, are Lead (throws stones 1 and 2), Second (3 and 4), Third / vice-skip (5 and 6) and Skip (7 and 8, and usually directs play from the house). Each player delivers two (2) stones per end, alternating with the opposing player in the same position. Players must hold the same position and throwing order throughout a game unless a permitted change is made.

A player delivers by pushing off from the hack and sliding forward, releasing the stone with a gentle rotation (turn) that makes it curl. The stone must be clearly released from the player's hand before it reaches the nearer (home) hog line. The delivering player may not touch the stone after release. Each end uses eight (8) stones per team (16 in total), thrown alternately. The team that does not have last-stone advantage (the hammer) delivers first in the end.

If a player cannot continue (injury or illness), a team may bring in its alternate or reorganise its line-up. When a substitution is made, the team's players may not move to a position ahead of the one they held before (e.g. a Lead may not become Skip during the game), preserving competitive integrity; the substitute normally takes the vacated position or the team rotates within the rules. A team reduced below the minimum number of players permitted to deliver may have to play with reduced stones or forfeit, as specified in the Rules of Competition.

Sweeping with the brush warms and polishes the ice ahead of a moving (running) stone, reducing friction so the stone travels farther and curls less. Between the tee lines, any number of a team's own players may sweep its own stone. Only one (1) player may sweep behind the tee line. The non-delivering team's skip or vice-skip may sweep an opponent's stone only behind the tee line (to try to carry it through the house). Sweeping motion must be side to side, leaving no debris, and must finish to the side of a stopping stone.

The Free Guard Zone (FGZ) is the area between the hog line and the tee line, excluding the house. Under the current Five-Rock Rule, any opposing stone resting in the FGZ may not be removed from play (knocked out of bounds) until five (5) stones have come to rest in that end - that is, the sixth (6th) delivered stone is the first that may take a guard out of play. A stone moved earlier in violation is replaced to its original position and the offending stone (and any it displaced) is handled per the rules. This rule keeps guards in play and rewards strategic, high-scoring ends.

A moving stone that is touched by a player, brush or clothing is said to be burned. If a stone in motion is touched, the non-offending team chooses the remedy: (a) remove the touched stone and replace any stones it displaced; (b) leave all stones where they came to rest; or (c) place all displaced stones (including the touched one) where the non-offending team believes they would have come to rest. Under the Spirit of Curling, the team that burns a stone is expected to declare it themselves.

A delivered stone must be clearly released before the front of the stone reaches the nearer (home) hog line. If the player is still in contact with the stone when it crosses that hog line, a hog-line violation occurs and the stone is removed from play immediately (and any stones it displaced are replaced). At major championships an electronic handle (the 'eye on the hog') detects whether the stone was released in time, lighting green for a legal release and red for a violation. A stone that does not reach the far hog line is also removed from play (unless it strikes another stone in play).

A stone that crosses the back line entirely, or that touches a side line or goes outside the side boards, is out of play and removed immediately. A stone delivered in the wrong rotation by mistake is allowed to play out, but a stone delivered by the wrong player or out of turn is corrected: the non-offending team may declare the end replayed or accept the position; an extra or missed stone is rectified so each team delivers exactly eight per end.

After all 16 stones are delivered, the end is scored. Only one team scores per end: the team with the stone closest to the button scores one (1) point for each of its stones that is closer to the button than the opponent's nearest stone. A stone counts only if it is in or touching the 12-foot house. The maximum score in one end is eight (8) (a rare 'eight-ender'). The score is agreed by the vice-skips, who measure with a device if a decision is too close to judge by eye.

Throwing the last stone of an end is called having the hammer and is a major strategic advantage. The team that scores in an end loses the hammer, delivering first in the next end. If an end is blanked (no team scores), the hammer stays with the team that held it. The initial hammer is decided before the game (commonly by the Last Stone Draw, see 6.4, or by coin toss in lower-level play).

A blank end occurs when no stone is counting in the house after all 16 are thrown - neither team scores. A team holding the hammer may deliberately blank an end (e.g. by removing all stones from the house) to keep the hammer for a later, more favourable end. In a blank end the score does not change and the hammer is retained by the team that had it.

At World Curling championships the initial hammer is decided by the Last Stone Draw (LSD): before the game (during practice) each team draws stones to the button, and the distance (in cm) from the stone to the pin/button is measured. The team with the smaller total LSD distance earns the hammer in the first end. Cumulative LSD distances are also used as a tie-breaker in the standings to rank teams of equal record, so teams take LSD seriously throughout the round robin.

A standard men's and women's championship game is played over ten (10) ends. Many club, junior and shorter-format games are played over eight (8) ends. Mixed doubles games are eight (8) ends (see Chapter 8). The team with the higher total score after the final end wins; if the scores are level, the game proceeds to extra ends (see 7.4). The game can also end early by concession.

Championship play uses thinking time rather than a fixed shot clock: each team has a budget of time that runs only while that team is deciding and playing its shot, and it stops once the delivered stone reaches the far tee line. For a 10-end game each team has 38 minutes of thinking time; an 8-end game uses a proportionally reduced allowance (about 30 minutes). Mixed doubles teams have 22 minutes for the 8-end game. Each extra end adds 4 minutes 30 seconds (standard) or 3 minutes (mixed doubles). A team that exhausts its thinking time forfeits the game.

Each team is entitled to one (1) team timeout of 60 seconds per game, called by the skip or coach; the timeout clock includes the time for a coach to travel onto the ice. In extra ends, each team is entitled to one additional 60-second timeout. The thinking-time clock stops during a called timeout and during any technical timeout declared by the officials (e.g. equipment failure or to repair the ice). A timeout must be requested at the proper moment (when the requesting team is in control of play).

If the score is tied after the final regular end, one or more extra ends are played until one team scores more than the other in an extra end; the team that did not score the last regular end (or won the LSD scenario per competition rules) typically starts with the hammer. A team may concede (shake hands) when it judges the game can no longer be won; at World Curling events conceding is generally permitted after a stated minimum number of ends (e.g. six ends in round robin, eight in play-offs). Conceding ends the game immediately and awards the win to the opponent.

Mixed doubles is an Olympic discipline played by a team of one woman and one man (2 players). A game is eight (8) ends. Each team delivers five (5) stones per end, but plays six (6) stones because one stone is pre-positioned in play before the end begins (see 8.2). One player delivers the team's first and last stones of an end, the other delivers the three (3) in between; players may swap this order between ends. There is no traditional four-player line-up - the two players also do all the sweeping.

Before each end, two stones are pre-positioned on the centre line: one as a guard in front of the house and one in the house (back half of the 4-foot circle, on the centre line). The team that did not score the previous end - and therefore holds the hammer - decides, before the end, the placement of the positioned stones. The team without the hammer owns the centre guard and delivers first; the team with the hammer owns the in-house stone and delivers last. There is no Free Guard Zone rule in mixed doubles; instead, no stone (including those in the house) may be removed from play before the fourth (4th) delivered stone of the end comes to rest.

Once per game, the team holding the hammer may call a power play: the two pre-positioned stones are placed off to the side of the sheet (the in-house stone toward the edge of the 8-foot circle on one side, the guard correspondingly to that side) instead of on the centre line, opening up the angles for a bigger score. The power play may be used only once per game and not in an extra end. The rest of the end then proceeds under normal mixed-doubles rules.

Wheelchair curling is a Paralympic discipline for athletes with a lower-body impairment. Standard wheelchair team play is over eight (8) ends with mixed-gender teams of four (4) (each team must include at least one male and one female player on the ice). Stones are delivered from a stationary wheelchair, either by hand or with an approved delivery stick (extender cue) that pushes the stone's handle. The thinking-time allowance and overall rules follow standard curling except for the wheelchair-specific provisions below.

The defining difference is that there is no sweeping in wheelchair curling - stones are delivered on weight and line alone, placing a premium on touch. During delivery the wheelchair must be held stationary (by a team-mate holding it or by an approved brake/restraint) and may not be moved while the stone is being pushed. All other scoring, hog-line, free-guard-zone and out-of-play rules apply as in standard curling. Wheelchair mixed doubles is also played (two players, with pre-positioned stones and likewise no sweeping).

World Curling events are run by a Chief Umpire, supporting umpires, a Technical Delegate and a Chief Ice Technician. Umpires enforce the rules, operate the measuring devices to decide close scores and biters, supervise the hog-line sensors and rule on violations and protests. Players themselves agree the score and call their own infractions under the Spirit of Curling; an umpire is normally called only when the two vice-skips cannot agree or a measurement is required. The Chief Umpire's decision on a point of rule is final at the event.

Breaches of conduct are sanctioned progressively. For an equipment violation (e.g. a non-approved brush head or stone), the first team offence typically results in the player being disqualified and the team forfeiting the game; subsequent or serious cases can lead to event disqualification. Unsporting behaviour, abuse of officials, or refusal to follow the rules may be penalised by warning, removal of a player or disqualification at the Chief Umpire's discretion. Anti-doping violations (using a banned substance without a valid TUE) and serious breaches of eligibility carry disqualification and possible suspension under World Curling and WADA rules.

International championships are normally played as a round robin followed by play-offs. Teams are ranked by win-loss record, with ties broken by head-to-head results and cumulative Last Stone Draw (LSD) distance. The top finishers advance to a play-off (commonly a Page play-off 1-2 / 3-4 system or direct semi-finals) leading to a bronze and gold medal game. The 2026 Olympic Winter Games (Milano Cortina) stage men's, women's and mixed doubles curling under this edition of the rules.

In October 2025 World Curling confirmed major competition-structure changes for the 2026-2030 Olympic cycle, effective from the 2026-27 season (after the current 2025-26 season). The men's and women's World Championships expand from 13 to 18 teams in two pools of nine, with pool winners advancing directly to the semi-finals, and a new tiered A / B / C Division promotion-relegation system is introduced (a 16-team B-Division each November; C-Division regional events). From 2027 the World Junior Championships move to 16 teams per gender in two pools of eight, all games played over eight (8) ends, with a new Junior-B division. These changes are upcoming and do not alter the 10-end championship format in force for 2025-26.