National Hockey League rules

Scope and structure of NHL rules

The NHL rulebook is an organized code used by players, coaches, officials and clubs. It defines period length, faceoff locations, substitution procedures (including on-the-fly changes), and the roles of referees and linesmen. Enforcement relies on on-ice officials and increasingly on video review for goal and interference determinations. The league publishes interpretations and supplemental discipline guidelines to handle dangerous plays and off-ice reviews.

Key differences from international rules

• Rink dimensions: NHL surfaces are narrower than typical international arenas, shaping player spacing and style of play.
• Overtime and tie resolution: the NHL uses shortened sudden-death overtime and a shootout in the regular season; international tournaments often use different overtime formats or continuous overtime in knockout stages.
• Enforcement and physicality: the NHL traditionally allows a higher degree of physical contact and tolerates fighting to a degree that international bodies usually prohibit.
• Icing and offside: the league uses hybrid-icing procedures and contemporary offside rules; variations exist in how delayed offside and reviewable offsides are handled in international play.

Penalties, power play and game flow

Infractions are classified as minor, major, misconduct and match penalties, each carrying specific time-serving and discipline consequences. Penalties create power plays for the non-offending team, a major strategic element of NHL games. The league also uses penalty shots in clear goal-scoring opportunities and applies supplementary discipline for actions that warrant fines or suspensions.

Overtime, shootouts and playoffs

Regular-season ties are decided by a brief sudden-death overtime followed by a shootout if necessary, producing a winner for each game. Playoff hockey, however, returns to continuous sudden-death periods of full length until a goal ends the game; shootouts are not used in postseason series.

History and notable developments

Over time the NHL has amended rules to improve safety, flow and scoring balance. Examples include eliminating the two-line pass restriction, adopting hybrid icing, introducing the regular-season shootout after the 2004–05 work stoppage, implementing broader video review and refining officiating systems. Differences with the International Ice Hockey Federation (IIHF) and events such as the Olympics underline how rule choices shape tactics and the spectator experience.