Football offside rule explained simply: Everything you need to know

If there is one rule in football that causes more confusion, debate and outright anger than any other, it is offside. Fans argue about it in pubs, analysts dissect it on television, and referees make career-defining decisions based on millimetres of shoulder. Here is everything you need to know.

The basic offside rule

A player is in an offside position if any part of their body that can legally play the ball is nearer to the opponent's goal line than both the ball AND the second-to-last opponent (usually meaning the last outfield defender, as the goalkeeper counts as an opponent).

Three conditions must all be met for a player to be penalised for offside:

1. The player is in an offside **position** when the ball is played by a teammate
2. The player **receives** the ball or becomes **actively involved** in play
3. The player is in the **opponent's half** of the pitch

Being in an offside position is not itself an offence. The offence occurs when a player in that position becomes involved in active play.

What body parts count?

Crucially, offside is judged on any part of the body that can legally play the ball: head, torso, arms up to the shoulder, and legs/feet. Hands and arms do not count — a player's arm can be ahead of the last defender and they are still onside, because you cannot legally score with your arm.

This is why VAR freeze-frames often show lines drawn through shoulders and chests rather than fingertips.

What is "active play"?

This is where it gets more complex. A player in an offside position is penalised if they:

• **Receive the ball** directly from a teammate
• **Interfere with play** — meaning they play or touch the ball
• **Interfere with an opponent** — blocking a goalkeeper's line of sight, for example, or physically obstructing a defender
• **Gain an advantage** from being in that position — such as receiving a ball that rebounds off the post or goalkeeper after being in an offside position when the original shot was taken

A player is not offside if they receive the ball directly from a goal kick, corner kick or throw-in — in these situations, there is no offside offence regardless of position.

The "second phase of play" question

One of the most debated aspects is what happens after the ball goes to an offside player but is played elsewhere first. The key question: was the sequence of play sufficiently "broken" to reset offside?

Under current Laws, offside resets when a defender deliberately plays the ball (not a deflection). If a defender makes a deliberate, purposeful play on the ball, any subsequent phase is judged fresh. An uncontrolled deflection from a defender does not reset offside.

How does VAR change offside?

Video Assistant Referee technology has made offside decisions significantly more accurate but also more controversial. The process works as follows:

1. The assistant referee keeps their flag down if it is a close offside call — VAR checks the decision
2. If the assistant has already flagged, VAR can only overturn if the flag was clearly wrong
3. For tight decisions, VAR analysts draw calibrated lines through the relevant body parts of both the attacker and the last defender at the moment the ball is played
4. The system is accurate to within roughly 1–2 centimetres

The controversy arises from the semi-automated offside technology (SAOT) now used in major tournaments including the Champions League and World Cup. This system tracks players automatically using cameras and data points, generating much faster offside decisions — typically within 30–40 seconds rather than several minutes.

Common misunderstandings

"He was level, so he's onside." Correct — a player who is level with the last defender is onside, not offside. The rule says "nearer to the goal line," so level is always onside.

"But his arm was ahead." Arms do not count for offside unless the ball directly strikes an arm that is in an unnatural position. Standard arm positioning is ignored.

"He wasn't interfering." Standing near a goalkeeper and distracting them counts as interfering with an opponent. You do not need to touch the ball to be penalised if you actively distract the keeper.

"The ball touched a defender first." If the defender deliberately played the ball (a controlled touch, a clearance attempt), offside is reset. If the defender simply deflected an unstoppable shot, offside is not reset.

Offside in practice: Attacking team tactics

Modern teams actively exploit the laws around offside. Common tactics include:

• **Dummy runs:** Players run into offside positions to drag defenders away, then others run into space from onside
• **Timed runs:** Forwards time their runs to be onside at the exact moment the ball is played, even if they were previously deeper
• **Second-phase positioning:** After an initial shot, forwards position themselves to receive a rebound while remaining onside at the moment of the original shot

Defensive teams counter with offside traps: coordinated lines stepping up precisely as the ball is played forward, catching attackers in offside positions.

Recent rule clarifications (2027–28)

IFAB (the body that makes the Laws of the Game) has clarified several interpretations in the 2027–28-26 edition:

• **Deliberate play by defender:** Greater clarity on what constitutes "deliberate" — any attempt to control or direct the ball, even if it goes elsewhere
• **Interfering with an opponent:** Expanded guidance on when a player in an offside position is considered to be making play harder for an opponent
• **Semi-automated offside:** SAOT is now mandated at all top-level international tournaments, with the technology being rolled out to domestic leagues

Frequently Asked Questions