Decisions
The offside rule explained
Offside is one of the most asked-about rules in football. The idea behind it is simple, but the detail is where most confusion comes from. This guide explains it step by step.
Why offside exists
The offside rule stops attacking players from simply waiting near the opposition goal for a pass.
Without offside, an attacker could stand by the goalkeeper for the whole match and wait for a long ball. The rule keeps attackers from gaining an unfair advantage by being closer to the opposition goal than the defenders, and it shapes how teams attack and defend.
In practice, offside means that an attacker has to time their runs and stay roughly level with the defenders until the ball is played to them.
Offside position
Being in an offside position is not, on its own, an offence. It is the starting point for a possible offside decision.
A player is in an offside position if any part of the head, body or feet is in the opponents' half and closer to the opposition 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.
A player is not in an offside position if they are in their own half, including if they are level with the halfway line. They are also onside if they are level with the second-last opponent or with the last two opponents.
When offside is given
An offside offence happens only when a player in an offside position becomes involved in active play.
Interfering with play
Touching or playing the ball that has been passed or touched by a teammate.
Interfering with an opponent
Preventing an opponent from playing the ball, blocking their line of vision, or challenging them for the ball.
Gaining an advantage
Playing the ball, or interfering with an opponent, after it rebounds or deflects off the goalpost, crossbar, match official or an opponent, or after it has been deliberately saved by an opponent.
The moment that matters
Offside is judged at the moment the ball is played by the attacker's teammate, not when it arrives.
The offside decision is based on the position of the attacker at the exact instant their teammate plays or touches the ball. If the attacker is onside at that moment, they cannot be flagged offside even if they then run past the defensive line.
This is why offside often looks close. Modern broadcasts pause on the moment of the pass and draw lines across the pitch to show where attackers and defenders were standing at that frame. In technical decisions, the first point of contact is normally used for the pass or touch, although goalkeeper throws are judged from the release of the ball.
Common situations
A few situations come up often enough that they are worth knowing in detail.
Passive offside
A player in an offside position who is not interfering with play or with an opponent is not penalised. The flag stays down until they get involved.
Onside from a restart
A player cannot be offside directly from a goal kick, a corner or a throw-in, even if they are clearly beyond the last opponent.
Deflections and deliberate play
A rebound or deflection off an opponent does not reset offside, and neither does a deliberate save. However, if an opponent deliberately plays the ball with enough control, such as a controlled clearance, pass or touch, the attacker is usually no longer gaining an offside advantage.
Coming back from offside
A player who was offside at the moment of the pass remains offside until the next clear phase of play resets the situation. Running back into an onside-looking position does not cancel the original offence.
The restart
If offside is given, the defending team restarts with an indirect free kick from where the offside offence happened, even if that place is in the player's own half.
How offside is checked
Offside calls are made on the pitch and, in many competitions, double-checked by VAR.
The assistant referee on the touchline is in the best position to judge offside live and raises a flag when they see an offence. To avoid stopping a possible goal-scoring move too early, the flag is sometimes delayed until the move has played out.
In competitions that use VAR, offside decisions on goals are reviewed using broadcast cameras. Some competitions also use semi-automated offside technology, which combines player and ball tracking to help VAR identify offside positions more quickly. Some systems also use connected ball technology to help identify the kick point.
Offside and the offside trap
Offside also shapes how teams defend, especially when they use a high defensive line.
A defence can use the offside rule as part of its tactical shape. When the back line steps forward together as a pass is played, attackers who were trying to run in behind may be left closer to goal than the second-last opponent.
This is known as the offside trap. It depends on timing, communication and defenders moving as one line. If one defender stays deeper than the others, the attacker may be played onside and the defending team can be exposed.
What to read next
Offside often comes up in the same conversation as fouls, free kicks and refereeing decisions.