How Offside Happens in Football: Rule Explained

What the Offside Rule Actually Says

The offside rule is one of the most debated rules in football, but the core is simple. A player is in an offside position if they are in the opponent’s half and closer to the opponent’s goal line than both the ball and the second-last opponent. The “second-last opponent” usually means the last outfield defender, because the goalkeeper is normally the last opponent. So if an attacker is level with the last defender, they are not offside. If they are behind that defender when the ball is played, they are offside — but only if the referee decides they are involved in active play.

Being in an offside position is not an offence by itself. The offence only occurs when the ball is played or touched by a teammate and the player in the offside position becomes involved in play. This involvement can be by touching the ball, interfering with an opponent, or gaining an advantage from being in that position.

Key Points to Understand Offside

Position is judged at the moment of the pass — The offside decision is based on where the attacker is when the ball is played by a teammate, not when the attacker receives it. If the attacker is behind the defender when the pass is made but sprints past them before the ball arrives, they are offside.
The second-last opponent is the line — The attacker must be level with or behind the second-last opponent (usually the last outfield defender) to be onside. The goalkeeper is the last opponent, so the defender nearest the goal is the second-last.
Must be in the opponent’s half — A player cannot be offside in their own half. The halfway line acts as a boundary; if the attacker is in their own half when the ball is played, they are always onside.
Active play matters — Merely being in an offside position is not a foul. The player must touch the ball, interfere with an opponent, or gain an advantage. If they do none of these, no offside is given.
No offside from goal kicks, throw-ins, or corners — These restarts have special rules. You cannot be offside directly from a goal kick, a throw-in, or a corner kick. This is a common source of confusion.
Deliberate play by a defender resets offside — If a defender deliberately plays the ball (e.g., a clearance or a back pass), the offside position is reset. The attacker can then receive the ball even if they were offside before the defender touched it.

What Counts as “Interfering with Play”

The phrase “interfering with play” is where most arguments start. The Laws of the Game define three ways a player in an offside position can be penalised:

Interfering with play — Touching the ball after it has been played by a teammate.
Interfering with an opponent — Preventing an opponent from playing or being able to play the ball by obstructing their line of sight or movement, or making a gesture that deceives them.
Gaining an advantage — Playing the ball after it has rebounded off the goalpost, crossbar, or an opponent, having previously been in an offside position.

For example, if an attacker stands offside and blocks the goalkeeper’s view of a shot, that is offside. If they stand offside but do not affect the play, the referee will let play continue. The key is whether the player’s position has an impact on the game.

Common Misconceptions and Confusing Situations

One of the most frequent misunderstandings is that offside is judged when the ball is received. In reality, it is judged when the ball is played forward. Another common error is thinking a player is offside if they are simply ahead of the ball — but that is only part of the condition. The position of the defenders also matters.

Another tricky area is when a defender accidentally deflects the ball to an offside attacker. If the deflection is not deliberate, the offside still stands. If the defender makes a deliberate save or clearance, the offside is reset. The distinction is whether the defender had control and intention.

Also, a player cannot be offside from a throw-in, even if they are standing directly in front of the goal. This is a specific exception in the laws. Similarly, a goal kick cannot produce an offside, which is why teams sometimes use short goal kicks to build from the back.

How Referees and VAR Make the Call

The referee and the assistant referees (linesmen) are responsible for spotting offside. The assistant referee watches the second-last defender and the attacker in real time, and they raise the flag when they believe an offside offence has occurred. The referee then stops play and awards an indirect free kick to the defending team from the spot where the offside player became involved.

With the introduction of Video Assistant Referee (VAR), offside decisions can be reviewed. The VAR uses camera angles and computer-generated lines to determine the exact position of the attacker and the defender at the moment the ball is played. This has made decisions more accurate but also led to debates about “toenail offsides” — where a player is ruled offside by a matter of centimetres. The VAR only intervenes when there is a clear and obvious error, but for offside, the decision is purely factual.

Why the Rule Exists and How It Has Changed

The offside rule was created to prevent attackers from simply standing next to the goalkeeper and waiting for a long ball. It keeps the game fair and encourages attacking play that involves passing and movement. Without it, football would become a game of long punts towards a stationary striker.

The rule has evolved over time. Originally, a player was offside if they were ahead of the ball and there were fewer than three opponents between them and the goal. This was later changed to two opponents, which is the current standard. The “active play” clarification was added to reduce the number of stoppages for players who were offside but not affecting the game. More recently, the law was amended to state that an attacker who is in an offside position but does not touch the ball and does not interfere with an opponent is not penalised.

Frequently Asked Questions

Can you be offside from a throw-in?

No. The Laws of the Game specifically state that there is no offside offence directly from a throw-in. This means a player can receive a throw-in even if they are behind the last defender.

What is the difference between offside and offside position?

Offside position is simply where a player is standing — closer to the goal line than the ball and the second-last opponent, in the opponent’s half. Offside is the offence that occurs when a player in that position becomes actively involved in play. A player can be in an offside position without committing an offence.

Does a defender’s touch make you onside?

Only if the touch is deliberate. If a defender deliberately plays the ball (e.g., a clearance), the offside is reset. If the ball deflects off a defender unintentionally, the offside offence still stands. The referee must judge the defender’s intention.

Can a goalkeeper be offside?

Yes, a goalkeeper can be offside if they are in the opponent’s half and ahead of the ball and the second-last opponent. This is extremely rare, but it is possible if the goalkeeper comes up for a corner and the ball is cleared to them.

What happens after an offside is given?

The referee awards an indirect free kick to the defending team from the spot where the offside player became involved in play. If the offside player is in their own half, no offside is given, so the free kick is always taken in the attacking half.

Why do attackers sometimes stay behind the last defender?

To avoid being offside, attackers time their runs so they are level with or behind the last defender when the ball is played. This is called “timing the run” and is a key skill for strikers. They wait until the pass is made before sprinting forward.

Sources: The IFAB Laws of the Game. Menus and buttons can differ slightly by version. Spotted something out of date? Tell us.