How does VAR actually decide an offside call?

[Scarlett89]

Semi automated offside technology works by tracking specific skeletal points on every player on the pitch using multiple dedicated cameras positioned around the stadium, typically around 29 or more, all recording at extremely high frame rates. Combined with a sensor inside the match ball itself that detects the exact moment of contact when a pass gets kicked, the system can pinpoint precisely which frame the ball actually left the passer's foot.

At that exact frame, the system draws a virtual line based on the specific defending player's tracked body position, and compares it directly against the attacking player's tracked position at that same identical instant. If any part of the attacker's body that is legally allowed to score, generally excluding hands and arms, is beyond that defensive line at the moment the ball was actually played, the system flags the position as offside.

This is a genuinely meaningful upgrade from the earlier manual VAR process. Where a human official had to painstakingly draw those same lines by hand using video replay, a process that was noticeably slower and introduced real potential for small human error in exactly where those lines actually got drawn on screen.

The system does not actually make the final call entirely by itself though. It generates the specific positional data and a recommended decision, but a human video assistant referee still reviews that data and the actual match officials on the pitch make the final official call, the technology functions specifically as a genuinely precise measurement tool assisting human judgment rather than as a fully independent automated decision maker.

So the actual speed improvement fans notice mainly comes from automating the tedious and error prone process of measuring exact player positions. Not from removing human officiating from the equation entirely, a real person is still very much involved in confirming and delivering every single final call