The offside rule, Law 11 of the Laws of the Game, is the rule fans argue about most. Once you understand the two key questions, though, it is simple.

Question 1: is the player in an offside position?

A player is in an offside position if, at the moment a teammate plays or touches the ball:

• any part of the head, body or feet is in the opponents’ half, and
• that part is nearer to the opponents’ goal line than both the ball and the second-last opponent.

The second-last opponent is usually the last outfield defender, because the goalkeeper is normally the last opponent. Hands and arms do not count when judging the position.

Question 2: is the player involved in play?

Being in an offside position is not an offence on its own. The player is only penalised if they become involved in active play, by:

• playing or touching the ball,
• interfering with an opponent, for example blocking the goalkeeper’s line of vision, or
• gaining an advantage, such as playing a ball that rebounds off the post or the goalkeeper.

When you cannot be offside

• In your own half.
• Level with the second-last opponent or level with the ball.
• Directly from a goal kick, a throw-in or a corner kick.
• When the ball comes from a deliberate play by an opponent, other than a save.

What happens after an offside offence?

The referee awards an indirect free kick to the defending team at the place where the offence happened. The assistant referee signals by raising the flag.

VAR and semi-automated offside

Video assistant referees check offside decisions before goals are confirmed. Many competitions, including the World Cup, the Champions League and the Premier League, now use semi-automated offside technology, which tracks players’ limbs with multiple cameras to produce a 3D image of the decision within seconds.

Why the rule exists

Without offside, attackers could wait next to the goalkeeper for long balls. The rule encourages teamwork and passing, and it is why defences push up to create an offside trap. Learn about the roles on the pitch in our guide to football positions and how teams line up in our formations guide.