What is an offside position in football? The rule explained

An offside position is a position on the pitch, not an offence. A player is in an offside position if any part of the head, body or feet is in the opponents' half, excluding the halfway line, and any part of the head, body or feet is nearer to the opponents' goal line than both the ball and the second-last opponent. Being in an offside position is perfectly legal. It only becomes a problem, under Law 11, if the player gets involved in active play, and even then only at the moment the ball is played by a team-mate.

The strange part is that everyone argues about the wrong thing. The offside position itself is completely objective, a geometry question that a computer can answer. The parts of the law that actually require judgment, what counts as interfering and what counts as deliberate play, are the parts the VAR technology cannot touch, and the more precisely we measure the position, the more absurd the law's exceptions look.

What counts as an offside position

Two conditions must both be true at the moment the ball is played or touched by a team-mate, and both use only the head, body and feet. The hands and arms of all players, including the goalkeepers, are not considered, and for determining offside the upper boundary of the arm is in line with the bottom of the armpit.

Condition one is location. The player must be in the opponents' half, and the halfway line itself does not count as being in it. A player exactly level with the halfway line is in his own half, so he cannot be in an offside position.

Condition two is closeness to the goal. The player must be nearer to the opponents' goal line than both the ball and the second-last opponent. "Nearer" means any part of the head, body or feet closer, which is why the armpit line matters: a striker played through with only his arm ahead of the defender is onside, because the arm is not part of the equation. A millimetre of sleeve is onside; a millimetre of shoulder is offside.

The second-last opponent and the keeper assumption

The second-last opponent is usually the last defender, because the last opponent is usually the goalkeeper. The law does not require that. If a defender is left behind the play, a striker one-on-one with the goalkeeper is judged against both the defender and the keeper, meaning the striker can be offside even though he is behind the defence.

A player is not in an offside position if he is level with the second-last opponent, or level with the last two opponents, or in his own half. The "level" rule dates from 1990, when the law was changed so that level with the second-last defender is onside, giving the attacker the benefit of the doubt in any genuinely level situation.

Position is not an offence: the active play test

This is the part most people miss. A player in an offside position is only penalised if, at the moment the ball is played or touched by a team-mate, he becomes involved in active play in one of three ways:

• Interfering with play: playing or touching a ball passed or touched by a team-mate.
• Interfering with an opponent: preventing an opponent from playing the ball by clearly obstructing his line of vision, challenging an opponent for the ball, clearly attempting to play a ball that is close when that action impacts on an opponent, or making an obvious action that clearly impacts on the ability of an opponent to play the ball.
• Gaining an advantage: playing a ball that rebounds or is deflected off the goalpost, the crossbar or an opponent.

Timing is everything. Offside is judged at the moment the ball is played, not when the player receives it. A player can be behind the defence and clearly in an offside position at the moment of the pass, run onto the ball, and still be onside if the pass was played before he crossed the line of the second-last opponent. The position also resets every time the ball is played by a different player, so a second pass can rescue a player who was offside for the first, and a deflection or rebound that creates a chance has to be judged by the gaining-advantage test.

How the position is measured

Since the Premier League introduced semi-automated offside technology at Matchweek 32, 12-14 April 2025, the position has been measured by tracking data rather than by hand. UEFA first used the system in the Champions League from 2022/23 and FIFA at the World Cup in Qatar, and the technology draws the lines that used to be drawn by hand. It does not change what offside is. It changes how quickly and consistently the position is measured, and it does not remove the judgment calls, which still sit with the on-field officials and the video assistant referee.

VAR reviews goals that hinge on an offside decision, which means the goal is checked, and the semi-automated lines usually settle the position question within seconds. What the technology cannot settle is the active play question, because that requires reading the attacker's intent, and no camera does that. The 2023 clarification that deliberate play turns on ball control narrowed one debate and left the other exactly where it was.

The exceptions and the 2026/27 state of play

There is no offside at all if the ball comes directly from a goal kick, a throw-in or a corner kick. A throw-in can be hurled into the six-yard box at a striker standing between the keeper and the goal line with no flag, and a goal kick can be played directly to a striker standing behind the defence. A free kick is not an exception: the offside law applies fully to free kicks, which is why the attacking team's wall games are so carefully staged.

When a player does commit an offside offence, the punishment is an indirect free kick to the defending team. For the 2026/27 season the offside law is unchanged, after its latest amendments in 2018, 2021 and 2023: the first point of contact with the ball rule, the armpit line and the deliberate play clarification. The next change, if it happens, would be bigger. The "Wenger offside" proposal, named after its advocate and now associated with Arsenal's former manager, would only penalise an attacker when his entire body is beyond the second-to-last opponent, and it is only a trial in the Canadian Premier League, with results going to IFAB at the end of the year. Our guide to the 2026/27 rule changes covers the full slate, and the guide to the offside rule has the complete law. That is the whole picture of the offside position: objective to measure, subjective to judge, and unchanged for the season ahead.

FAQ

What is an offside position? A player is in an offside position if 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. The hands and arms do not count, and being in an offside position is not an offence by itself.

Is it offside if a player is level with the last defender? No. A player level with the second-last opponent, or level with the last two opponents, is not in an offside position. The 1990 law change gave the attacker the benefit of the doubt in level situations.

When is a player actually penalised for being offside? Only when he is in an offside position at the moment the ball is played by a team-mate and then becomes involved in active play by interfering with play, interfering with an opponent or gaining an advantage.

Can a player be offside from a throw-in or corner? No. There is no offside offence if the ball is received directly from a goal kick, a throw-in or a corner kick. Free kicks are not exempt.

What is the punishment for an offside offence? An indirect free kick to the defending team.

Key takeaways

• An offside position is purely positional: any part of the head, body or feet in the opponents' half and nearer to the goal line than both the ball and the second-last opponent, with hands and arms excluded.
• The armpit line, in place since 2021, makes the measurement absurdly fine: a millimetre of sleeve is onside, a millimetre of shoulder is offside.
• Being in an offside position is not an offence; the offence requires active play, and the judgment part of the law is the part technology cannot settle.
• Offside is judged at the moment the ball is played, not when it is received, and the position resets every time a different player touches the ball.
• Goal kicks, throw-ins and corners are exempt, free kicks are not, and the law is unchanged for 2026/27, with the offside position still decided by the head, body or feet test alone.