What Is VAR in Football and How Does It Work?

The Philosophy: "Minimum Interference, Maximum Benefit"

The Video Assistant Referee (VAR) system was formally codified into the IFAB Laws of the Game in 2018 following international trials at the FIFA Club World Cup and 2018 World Cup in Russia. Its foundational mandate is straightforward: "minimum interference, maximum benefit."

VAR is not designed to re-referee matches or achieve theoretical perfection on every minor decision. Instead, it serves as a safety net against "clear and obvious errors" or "serious missed incidents" occurring during critical match-defining situations.

The Four Match-Changing Incident Categories

Under strict IFAB protocols, VAR can only intervene in four specific game situations. Every other decision—such as corner kicks, regular throw-ins, and standard yellow cards—cannot be reviewed by VAR.

• Goal / No Goal: Infractions leading up to a goal in the attacking possession phase (fouls, handball, ball going out of bounds, offside).
• Penalty / No Penalty: Incorrect award or non-award of a penalty kick inside the 18-yard box.
• Direct Red Card: Incidents involving violent conduct, serious foul play, spitting, or denial of an obvious goal-scoring opportunity (DOGSO). Second yellow cards cannot be reviewed.
• Mistaken Identity: When a referee cautions or sends off the wrong player.

Step-by-Step: How a VAR Check Operates

A silent check is continuously conducted by the VAR team in the Video Operation Room (VOR) during active play. When a potential incident arises, the workflow follows four precise steps:

• 1. Incident Occurs: The referee makes a decision or play continues following an uncalled foul in a scoring phase.
• 2. Silent Check: The VAR team reviews synchronized multi-angle broadcast feeds and high-speed camera angles.
• 3. Communication: If evidence suggests a clear and obvious error, the VAR radios the lead official via the audio headset recommending an intervention.
• 4. Decision: The on-field referee either accepts factual advice (e.g., offside location) or visits the pitchside monitor for an On-Field Review (OFR).

On-Field Review (OFR) vs. Factual Decisions

Factual decisions do not require the referee to view the screen. These include geometric offside determinations, whether a foul occurred inside or outside the 18-yard penalty box, or whether the ball crossed the touchline.

Subjective decisions—such as the force of a tackle for a red card, whether a handball contact was unnatural, or whether contact warranted a penalty—require an On-Field Review (OFR) at the pitchside monitor so the primary referee retains ultimate decision authority.

Semi-Automated Offside Technology (SAOT)

Introduced in elite competitions like the FIFA World Cup, UEFA Champions League, and top domestic leagues, Semi-Automated Offside Technology (SAOT) utilizes dedicated tracking cameras mounted beneath stadium roofs.

These cameras track 29 optical data points per player 50 times per second, paired with an inertial measurement unit (IMU) sensor inside the ball that transmits kick-point data at 500Hz. This generates precise 3D offside lines within seconds, vastly reducing waiting times for spectators.

To understand the baseline rules governing Law 11 that VAR enforces, review our guide to what is offside in football.