The whole-ball rule

The ball is out of play only when the whole of the ball has fully crossed the boundary line — touchline or goal line — on the ground or in the air.

That last word matters. The ball can be 99% over the line and still be in play. The defender who hooks a ball back from what looks like a hopeless position has not always made an impossible save — they may simply have made contact while a sliver of the ball was still on the line.

Lines are part of the field

The touchlines and goal lines are part of the playing area. A ball resting on the line is in play. A ball that has crossed half the line is in play. The boundary is not the line — the boundary is the far edge of the line.

This is why goal-line technology exists. Determining whether a 22-centimetre ball has fully crossed a 12-centimetre line at high speed is genuinely hard for the human eye.

What happens when it goes out

Each restart depends on where and who:

• Over the touchline: throw-in to the team that did not touch the ball last
• Over the goal line, last touched by attacker: goal kick to the defending team
• Over the goal line, last touched by defender: corner kick to the attacking team
• Fully over the goal line between the posts and under the bar: a goal

The "last touched" rule is the same logic for both touchlines and goal lines. Whoever touched it last loses possession.

Goal-line technology

For goals only, technology confirms whether the whole ball has crossed the goal line. A signal is sent to the referee's watch within a second. Major leagues and tournaments use this; lower divisions still rely on assistants and the referee.

For touchlines, no automated system exists in any major competition. The assistant referee on each touchline tracks the ball and signals out-of-play decisions with their flag.

Common confusions

• "Half the ball is over — that's out." No. The whole ball must cross.
• "It bounced back in, so it's still in play." Only if it never fully crossed. A ball that fully exits and spins back is out — the moment of crossing is what counts.
• "The line is out." The line is part of the field, so a ball on the line is in.

A simple example

A defender chases a long ball toward the corner flag. They reach the ball just as it is rolling over the touchline. From the camera angle it looks gone. The ball is hooked back into play — and the assistant referee keeps the flag down. Replay shows that, at the moment of the touch, a small portion of the ball was still over the line.

The defender's touch was legal. Play continues.

Why this rule exists

A clear, single boundary makes restarts simple. There is no "mostly out" or "almost out." The ball is in or it is out, decided by a binary test: has every millimetre of it crossed the line?

The trade-off is that the eye sometimes sees out when the law says in. That is what makes goal-line technology valuable for the most important boundary on the pitch.