The Offside Rule in Football Explained Simply

Under the offside rule, a player is offside in football when they are nearer to the opponents’ goal line than both the ball and the second-last defender at the moment a teammate plays the ball to them, and they then get involved in play. Being in that position is not an offence by itself. The offence only happens when the player takes part in the action, which is the detail most people miss.

The offside rule in one sentence

Think of the offside rule as a line that moves with the defenders. When a pass is played forward, an attacker must have at least two opponents (usually the goalkeeper and one defender) level with or closer to the goal line than they are. If there is only one, or none, the attacker is in an offside position.

The offside rule exists to stop attackers from simply waiting next to the goal for a long ball. It forces teams to move up the pitch together and keeps the game from turning into a lottery of hopeful punts.

Offside position versus an offside offence

These are two separate ideas, and the laws treat them separately.

Being in an offside position

A player is in an offside position if any part of the head, body or feet is in the opponents’ half (not counting the halfway line) and is closer to the opponents’ goal line than both the ball and the second-last opponent. Hands and arms are not counted. For judging position, the arm is taken to end at the bottom of the armpit, so a reaching arm cannot put anyone offside.

Committing an offence

Standing in that position only becomes an offence if, when the ball is played or touched by a teammate, the player then becomes involved in active play. That can mean:

• interfering with play by touching or playing the ball that a teammate passed or touched;
• interfering with an opponent, for example by blocking the goalkeeper’s line of sight or challenging for the ball;
• gaining an advantage by playing a ball that rebounds or is deflected off the goalpost, crossbar or an opponent after the player was in an offside position.

The key moment is when the pass is made, not when the attacker receives it. An attacker who starts level and runs past the defenders while the ball is travelling is onside, because position is judged at the instant of the pass.

Situations where the offside rule does not apply

There are some restarts where the rule does not apply. A player cannot be offside directly from:

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

You also cannot be offside in your own half of the pitch, and you are not offside if you are level with the second-last opponent or level with the last two opponents. “Level” is a handy word, because it means the attacker is given the benefit of the doubt. Also, a ball played backwards or sideways by a teammate can still create an offside position if you are ahead of the ball and the second-last defender, so direction of the pass does not matter. Only your position at the moment of the pass does.

What happens when offside is given

When the referee or assistant referee decides an offence has occurred, the opposing team is awarded an indirect free kick. It is taken from the place where the offending player was when they became involved in play. Because it is an indirect kick, a goal cannot be scored from it unless another player touches the ball first.

The assistant referee usually signals with a raised flag, and the referee decides whether to stop play. If the attacker is not yet involved, the flag may stay down for a moment until the situation becomes clear.

A quick walk-through

How teams use the offside rule

Defending teams often use the rule on purpose. A back line that steps forward together as a pass is about to be played can catch attackers in an offside position. This is called the offside trap. It takes good communication, since one defender who does not step up can keep everyone onside.

Attackers fight against it with timing. Good forwards watch the line, begin their run from a deeper position and accelerate as the ball is played. The best of them seem to arrive from nowhere because they have waited for exactly the right second.

Technology and the modern game

Close offside calls are now often reviewed by the video assistant referee in competitions that use it. Some top tournaments have also introduced semi-automated systems that track players and the ball to help officials decide marginal calls faster. These tools help with accuracy, but the principle of the offside rule is unchanged. Understanding the pass moment, the second-last opponent and active involvement will explain nearly every decision you see.

If you are learning more about the sport, you might also enjoy our guides to the roles on a basketball court and the history of the Olympic Games, and you can find more in our sports section.

Frequently asked questions

Further reading: Wikipedia overview: Offside (association football).