The Offside Rule Explained — With Diagrams
Offside is not complicated once you separate the position from the offence. Here is the rule as the Laws actually write it, with diagrams and the youth-soccer version.
Offside is the law everyone argues about and almost nobody has read. It is also simpler than its reputation, as long as you hold two ideas apart: being in an offside position is not an offence. Being in an offside position and getting involved is.
Everything below follows Law 11 of the IFAB Laws of the Game, which is the rule book every competition in the world starts from.
Being in an offside position
A player is in an offside position when any part of the head, body or feet is in the opponents' half and nearer to the opponents' goal line than both the ball and the second-last opponent.
Three things fall out of that sentence, and all three are the bits people get wrong.
The second-last opponent, not "the last defender." Usually the goalkeeper is the last opponent and the deepest defender is the second-last, so the everyday shorthand works. But if the keeper charges upfield, the second-last opponent might be two outfield defenders back — and an attacker level with the deepest one is then onside.
Hands and arms do not count. You can be offside by a knee, a shoulder or a hair, but not by a fingertip. The Laws set the boundary precisely: the upper edge of the arm is in line with the bottom of the armpit. That line exists because you cannot score with your arm, so an arm that is ahead is not an advantage.
Level is onside. If the attacker is level with the second-last opponent — or with the last two — there is no offside position at all. The Laws give the attacker the benefit of being exactly level.
The blue attacker on the right is nearer the goal line than both the ball and the second-last defender at the moment the ball is played: that is an offside position.
Move him back a stride so he is level with that defender and the position disappears. Level counts as onside.
Two more ways to not be offside
You cannot be offside in your own half. Every part of you that matters has to be in the opponents' half, and the halfway line itself does not count as being over it.
A player who is still inside his own half when the ball is played cannot be offside, however far he then runs.
You cannot be offside behind the ball. The rule is "nearer than both the ball and the second-last opponent" — so a player level with or behind the ball is fine no matter where the defenders are.
Behind the ball at the moment it is played: onside, with no defenders anywhere near.
Being involved: the part that makes it an offence
A player in an offside position is only penalised when they become involved in active play. The Laws give three ways that happens.
Interfering with play — playing or touching a ball passed or touched by a team-mate. This is the everyday one: the striker runs on to the through ball and shoots.
Interfering with an opponent — blocking the goalkeeper's line of vision, challenging for the ball, clearly attempting to play a ball that is close enough to matter, or making an obvious action that clearly affects an opponent's ability to play the ball. This is why a player lying on the ground in an offside position can concede a goal that has already gone in: if he made the keeper move, he was involved.
Gaining an advantage — playing the ball after it has rebounded or been deflected off the goalpost, the crossbar, a match official or an opponent, or after it has been deliberately saved by any opponent.
Standing in an offside position and doing none of those things is not an offence. A winger loitering beyond the last defender on the far side of the field while play goes on elsewhere is simply a winger standing in a slightly silly place.
Deliberate play versus a deflection
This is the distinction that produces the most arguments, and the Laws are careful about it.
If a defender deliberately plays the ball — a pass, a clearance, an attempted interception that he chose to make — and it reaches an attacker who was in an offside position, that attacker is not penalised. The defender's decision resets it. That holds even if the defender made a mess of it.
The exception is a deliberate save, which the Laws define as stopping, or trying to stop, a ball going into or very close to the goal. A save does not reset anything: an attacker who scores from a rebound off a saving goalkeeper, having been offside when the shot was struck, is offside.
And a deflection is not deliberate play at all. If the contact was instinctive, stretching, or the ball simply hit a defender who had no control over it, the original offside position still stands.
When the position is judged
At the moment the ball is played or touched by a team-mate — not when the attacker receives it. That is why a striker can be four yards clear when he collects the ball and still be perfectly onside, and why the assistant referee is watching the passer's foot rather than the runner.
When offside does not apply at all
There is no offside offence if a player receives the ball directly from a goal kick, a throw-in or a corner kick. That is the whole list. It is not "any restart" — a free kick and a drop ball are both ordinary play for offside purposes.
The restart
An offside offence is punished with an indirect free kick to the defending team, taken where the offence happened — including inside the offending player's own half, which surprises people.
Indirect means the ball must touch another player before a goal can be scored. The referee signals it by keeping an arm raised until that happens.
What the flag actually means
The assistant referee raises the flag when an offside offence has occurred, not when a player strays into an offside position. Increasingly, assistants are told to keep the flag down when a goalscoring chance is developing and to raise it after the phase finishes — so that a genuine chance is not wrongly killed off. A delayed flag is not indecision; it is the instruction.
Offside in American youth soccer
Small-sided youth soccer treats offside differently, and this is where most parents' confusion starts.
- At 4v4 — Under 8 and younger under U.S. Soccer's small-sided standards — there is no offside at all. There is also no goalkeeper.
- From 7v7 (Under 9 and Under 10) offside applies, but only between the build-out line and the goal line. A player cannot be offside between the halfway line and the build-out line. The build-out line is drawn across the field 14 yards from each goal line, and it does a second job: when the goalkeeper has the ball in hand or takes a goal kick, the other team has to drop behind it until the ball is put into play.
- From 9v9 (Under 11 and Under 12) and up, offside works normally.
Your state association or league can and does modify this — check your own competition's rules before you argue with a referee about it.
See our field, goal and ball sizes by age guide for the rest of the small-sided standards.
The myths worth killing
"He was offside, the flag went up." The flag going up is the referee's decision, not evidence of the position. Two different things.
"He was offside but he wasn't interfering." If he was in an offside position and did nothing that counts as involvement, he was not offside. There is no offence to be lenient about.
"You can't be offside from a header." You can. A header from a team-mate is a touch by a team-mate like any other. What you cannot be offside from is a throw-in — including a throw-in flicked on by a team-mate's head, because the ball was then touched by a team-mate and the offside position is judged afresh at that touch.
"He came back from an offside position, so he's fine." Position is judged when the ball is played. Running back afterwards changes nothing.
Want the rest of the rule book in plain English? Try our 17 Laws for new players and parents, or if you would rather be the one making these calls, how to become a referee.