Rugby Sevens vs Fifteens: What Changes When Half the Players Leave

Rugby sevens is not a separate code. It is rugby union played under World Rugby's Laws of the Game with a published list of variations, and most of those variations shorten the match or cut its stoppages. The headline differences: seven players a side instead of fifteen, halves of no more than seven minutes instead of forty, a three-player scrum, conversions that must be drop kicks taken within 30 seconds, and yellow cards that last two minutes instead of ten.

The one thing that does not change is the most important. Sevens is played on the same pitch.

The variations side by side

World Rugby publishes the sevens variations law by law, quoting the fifteens text and the wording that replaces it. These are the ones that shape a match, as they appear in the online law book in October 2026:

Two dating notes. The 60-second conversion limit in fifteens arrived as a global law trial for competitions starting after 1 January 2025, and World Rugby's law book still labels it a trial; the sevens 30-second limit is a standing variation. And because both law sets are revised regularly, the online law book is the authority for any particular season.

Fourteen players, the same field

Law 1 allows a field of play up to 100 metres between the try lines and up to 70 metres wide, with minimums of 94 and 68. The sevens variations leave Law 1 alone, and a 2014 review in Sports Medicine describes sevens as played "on the same field dimensions as the 15-man code".

The arithmetic is the whole story of the format. On a maximum-size pitch:

Each player has more than twice the ground to account for. In principle that thins the cover behind every tackle: a defender who misses in fifteens usually has team-mates within a few metres, while in sevens the next defender can be much further away. It is the simplest explanation for the running-heavy profile the research below describes, and the contrast between union and league — thirteen players against fifteen on a comparable pitch — is a milder version of the same effect.

What the research says about the physical load

The same 2014 review, by Ross, Gill and Cronin, reports that sevens players spend a larger proportion of a match running at high intensity than fifteens players, and that international sevens players match fifteens backs for speed over 10 to 30 metres but appear to have superior intermittent aerobic endurance. It also notes that many sevens players also play fifteens as backs or loose forwards.

Contact does not disappear when the scrum shrinks. A 2022 systematic review of collision studies concluded that, per minute, sevens players perform more tackles and ball carries into contact than fifteens players, even though a sevens match produces fewer collisions in total because it is shorter and has fewer players. Per minute played, the shorter game is more contact-dense, not less.

The clock and the restarts

Sevens is built around a very short match, and the variations protect playing time from stoppages:

• Conversions must be drop kicks within 30 seconds of the try being awarded, and the defending team gathers near its own 10-metre line instead of retreating behind its try line.
• The scoring team kicks off. In fifteens the side that conceded restarts play, so a team that has just scored usually receives the ball again. In sevens the scorer kicks off, so the side that conceded usually gets the next possession unless the kicking team wins the restart back.
• Restart kicks are policed by free-kicks. A sevens kick-off that fails to reach the 10-metre line or goes directly into touch gives the receiving team a free-kick, where fifteens offers a menu of options such as a retake or a scrum.
• Scrums form faster: teams must be ready within 15 seconds of the mark being made, half the 30 seconds the fifteens law allows.

Discipline, scaled to the match

A two-minute yellow card sounds lenient next to ten minutes. Measured against the length of the match it is roughly equivalent: two minutes is about 14% of a 14-minute sevens match, and ten minutes is 12.5% of an 80-minute fifteens match. The penalty for a sin-binning is a similar share of the game played a player down.

Extra time follows the same logic. A drawn knock-out match restarts after a one-minute break with periods of no more than five minutes, and the first team to score is declared the winner without any further play.