In short
The answer first
The ball is out of play when the whole ball completely crosses a touchline or goal line, on the ground or in the air, or when the referee stops play. It remains in play when it rebounds from a goalpost, crossbar or corner flag and stays on the field. Specific referee-contact situations can require a dropped ball.
Key takeaways
The whole ball must cross the whole line.
A ball touching the line remains in play.
Height does not change the principle; the full ball can cross in the air.
Rebounds from posts, the bar or a corner flag remain live if the ball stays on the field.
Contact with a match official can lead to a dropped ball in the situations defined by Law 9.
The line is part of the field
A ball can appear mostly outside while a small part still overhangs the line. In that case it remains in play. The decision concerns the full sphere of the ball, not only the point touching the grass.
The same standard applies to goal-line decisions and throw-ins. Camera angle can make a close call look clearer than it was for the official.
Rebounds usually keep the phase alive
A shot hitting the post and returning onto the field is live. So is a ball striking the corner flag and remaining within the boundary.
Players should continue until the whistle or a clear boundary decision. Stopping because the ball looked out can create an avoidable disadvantage.
When the referee becomes part of the event
The Laws identify circumstances in which the ball touching an official and remaining on the field leads to a dropped ball, including certain changes of possession or promising attacks.
Not every touch automatically stops play. The consequence of the contact matters under the current Law.
Source check
Sources and further reading
KickVerse uses primary governing-body material where a rule or competition format has an official source. Analysis terms can vary between data providers, so provider-specific definitions are identified rather than presented as universal laws.
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