Offside, Explained Simply

Offside is the rule that confuses new football fans the most. The core idea is simple, and this guide starts there — then covers the details that decide most of the arguments you'll see on a Saturday.

The one picture to remember

Imagine an invisible line drawn across the pitch, level with the second-last opponent — usually the last outfield defender, with the goalkeeper being the other one.

An attacking player is in an offside position if, at the moment a teammate plays the ball, they are nearer to the opponents' goal line than both that line and the ball itself.

That's the picture. Almost everything else is refinement.

Why "second-last opponent" and not "last defender"

You'll hear "the last defender" everywhere, including in the original version of this guide. It's a useful shorthand, and it's slightly wrong.

The Law counts opponents, not positions, and it counts two of them. Normally the goalkeeper is one and the deepest defender is the other, so "the last defender" gets you the right answer. But if a goalkeeper charges upfield for a late corner, there's no goalkeeper at the back at all — and the rule still works, because it simply uses whichever two opponents are furthest back.

Why the rule exists

Without it, an attacker could stand next to the goalkeeper for ninety minutes waiting for a long ball. Scoring would be trivial and the game would be dull.

Offside forces attackers to time their runs instead of camping near the goal, and it lets defences push up the pitch, which is what creates the compressed, contested middle third that modern football is played in.

The part everyone gets wrong: position isn't an offence

This is the single biggest misunderstanding, and it explains most of the shouting.

Being in an offside position is not against the rules. A player can stand in an offside position for the entire match and never commit an offence.

It becomes an offence only if, at the moment the ball is played by a teammate, that player then becomes involved in active play in one of three ways:

• Interfering with play — touching or playing the ball, or challenging for it.
• Interfering with an opponent — blocking a defender's path or line of vision, or making a movement that clearly affects an opponent's ability to play the ball. This is why a striker standing offside and ducking out of the way of a shot can still be penalised: he obstructed the goalkeeper's sight of it.
• Gaining an advantage from being in that position — playing a ball that has rebounded off a post, the crossbar, a match official, or an opponent's deliberate save.

So the assistant referee is answering two separate questions, in order. Was he in an offside position? And then: did he do anything about it?

Which parts of the body count

Only the head, body and feet are measured.

Arms and hands are excluded — for attackers and defenders both. The logic is straightforward: you can't legally score with your arm, so an arm hanging beyond the defensive line isn't an advantage worth penalising.

This is why frozen VAR images show lines drawn to a shoulder rather than a fingertip, and why a forward whose arm is clearly beyond the line can still be onside.

When offside cannot be given at all

Three restarts are exempt. There is no offside offence directly from:

• a throw-in
• a corner kick
• a goal kick

A player can receive the ball in the most offside-looking position imaginable from any of these, and play simply continues. Note the word directly — once the ball has been played on by a teammate, normal offside applies again.

And offside can only happen in the opponents' half. A player level with the halfway line counts as being in their own half, and is onside.

The moment that matters

Offside is judged at the instant the ball is played by the teammate, not when it arrives.

Two consequences follow, and they're the source of endless confusion:

• A player who was onside when the pass was played can sprint past the entire defence and be perfectly legal, however offside he looks when he collects it.
• A player who was offside when the pass was played stays offside even if he runs back into an onside position before touching it.

Speed is irrelevant. Who reaches the ball first is irrelevant. It's one frozen moment.

When a defender plays the ball

Here's the situation that produces the most disputed decisions.

If a defender deliberately plays the ball — a controlled clearance, an attempted pass, a genuine act of playing it — an attacker in an offside position is generally no longer penalised. The defensive action has, in effect, reset the situation.

But if the ball merely deflects off a defender who had no control over it, or rebounds off a deliberate save, the offside offence stands. A save is treated differently from a clearance precisely so that a striker can't loiter offside waiting for a parried shot.

The dividing line is whether the defender had control of what he was doing — whether it was a deliberate act or something that happened to him. That judgement is why two very similar-looking incidents can be given differently.

Where VAR comes in

Because the decision depends on a single frozen frame, it's genuinely beyond what a human eye can resolve at speed. An assistant referee is watching the passer and the line at the same time, from an angle, at full sprint.

This is why replay technology now checks tight offside calls, and why semi-automated systems using body-tracking have been introduced to speed the process up and remove some of the manual line-drawing. Our guide to how VAR works covers what the system can and cannot review, and why offside checks take longer than other decisions.

It's also worth knowing that offside is a factual matter, not a judgement call. That's why VAR can overturn it outright without the referee going to the monitor, unlike a penalty decision.

What happens when offside is given

Play stops. The defending team gets an indirect free kick — meaning a goal can't be scored directly from it — taken from where the offside player was standing when the ball was played to them.

That last detail catches people out. The free kick isn't taken from where the player received the ball, and it isn't taken from where the pass came from. It's the offside position itself, which can be deep in the defending team's half.

The short version

• Offside position: nearer the goal line than both the ball and the second-last opponent, in the opponents' half.
• Level is onside. Arms don't count.
• Position alone is not an offence — the player must interfere with play, interfere with an opponent, or gain an advantage.
• Judged at the moment the ball is played, not when it arrives.
• No offside from a throw-in, corner or goal kick.
• Result: indirect free kick from where the offside player was.