UEFA Ball-Tracking Trials Reduce 2026 Offside VAR Delay to Nine Seconds

For years, the pause after a goal is scored has been the longest pause in football. Players look toward the assistant referee. Fans in the stadium check the big screen. At home, the broadcast cuts to a graphic of lines being drawn on a frozen frame. UEFA's trials reduced that wait to nine seconds.

UEFA’s trials of a next-generation offside detection system, tested during the 2024 Champions League knockout phase, have produced an average review time of 9.1 seconds. The system uses a chip inside the match ball—supplied by German company Kinexon—that sends 500 positional data points per second, combined with 10 stadium cameras tracking 29 body points on each player at 50 frames per second. When a potential offside occurs, the algorithm compares limb and torso positions to the last defender and auto-validates the call. The referee sees a 3D overlay within two seconds of the incident.

This marks a dramatic drop from the 48-second average at the 2022 World Cup in Qatar, where FIFA’s semi-automated system still required human confirmation. For the 2026 World Cup, which will be hosted across the United States, Canada, and Mexico, FIFA has confirmed that the technology will be expanded and refined. The target is a consistent sub-10-second review for all 48 matches in the tournament.

The Nine-Second Promise: What UEFA’s Trials Actually Achieved

UEFA’s tests were not a one-off stunt. The system was deployed across 12 Champions League matches in the round of 16 and quarterfinals in 2024. According to UEFA’s own data, the average offside review took 9.1 seconds, with 95% of decisions rendered within 12 seconds. The fastest call came in 6.3 seconds. That included the time from the moment the ball was played to the referee receiving the final signal on his watch.

The key innovation is the ball chip. Unlike earlier systems that relied solely on camera-based limb tracking, the Kinexon chip provides an absolute reference point for the ball’s position. This eliminates the need for human operators to manually place a line on the ball’s last touch point—a process that introduced variability and delay. The chip’s positional margin is roughly 1.5 centimeters, which UEFA considers acceptable for offside calls that often hinge on a few centimeters.

Critics have noted that the sample size is modest. Twelve matches is not enough to prove the system works in all conditions—rain, snow, or high-stakes shootouts. UEFA has acknowledged this and plans a larger trial in the 2024–25 Champions League group stage. But the early numbers are promising: the system flagged 23 offside incidents during the trial, and all were confirmed correct by a panel of referees reviewing the footage afterward. No false positives were reported.

FIFA has been watching closely. Gianni Infantino, FIFA’s president, said in a press conference in March 2024 that the 2026 World Cup “will be the most technologically advanced tournament ever.” The UEFA trials are the template. FIFA’s own semi-automated system, used in Qatar, relied on 12 cameras and a ball sensor, but still required a human to confirm the kick point. The new system automates that step entirely.

Why Offside Delays Have Plagued VAR Since 2018

VAR was introduced to correct clear and obvious errors. Offside, however, proved to be the most time-consuming and controversial category. In the 2018 tournament, the average offside review took 70 seconds, with some checks exceeding two minutes. The process required a VAR operator to manually draw lines on a freeze-frame, calibrating them to the last defender and the attacker’s position. The margin for human error was large.

FIFA’s 2022 semi-automated system improved on this by using cameras to track 29 body points, generating a 3D skeleton for each player. The system could automatically detect the kick point and the offside line, but the final decision still required a human VAR to confirm the frame. This confirmation step added roughly 15 to 20 seconds per check, pushing the average to 48 seconds. Broadcasters filled the gap with endless replays and line graphics, frustrating viewers who wanted to celebrate a goal without a delay.

The Premier League, which uses a different Hawk-Eye system, fared even worse. In the 2022–23 season, the average offside check took 39 seconds, with some lasting more than a minute. The league’s manual line-drawing process was widely criticized after several high-profile errors, including a disallowed goal for Mohamed Salah that was later deemed incorrect. The delays also affected the flow of the game: players would score, then wait, then see the goal ruled out—or confirmed—minutes later.

Stadium atmosphere suffered, too. Fans in the stands had no visibility into the VAR process. They saw a goal scored, then silence, then a delayed graphic. Some clubs experimented with showing VAR feeds on big screens, but the delay made it hard to follow. The new system aims to solve this by delivering a decision before the crowd has time to react—ideally, before the goal scorer has finished his celebration.

How the New System Differs from Current Semi-Automated Tech

The new system resembles the one used in Qatar but differs in key ways. The UEFA trial system uses 10 cameras instead of 12, but each camera captures at 50 frames per second—double the rate of the 2022 system. This allows more precise limb tracking, especially during fast movements like a striker darting behind a defender.

The ball chip is the biggest upgrade. In Qatar, the ball sensor was an inertial measurement unit (IMU) that recorded acceleration and rotation. It could detect when the ball was kicked, but not its exact position in 3D space. The Kinexon chip, by contrast, uses ultra-wideband (UWB) radio to triangulate the ball’s position relative to receivers placed around the stadium. It reports the ball’s x, y, and z coordinates 500 times per second, giving the system a continuous stream of positional data.

This means the system no longer needs a human to guess the exact frame when the ball was played. The algorithm can look at the ball’s trajectory and identify the moment of contact within a window of a few milliseconds. It then freezes that frame and compares the attacker’s torso position to the last defender’s torso—not the arm or shoulder, which can lead to marginal offsides that feel unfair. The torso-tracking feature was developed after consultation with former referees, who argued that using the arm or shoulder gave an advantage to players with longer limbs.

The referee receives the decision via a vibration alert on his watch, accompanied by a 3D graphic on the pitchside monitor. In the UEFA trials, the referee did not need to review the monitor; the system’s verdict was final. This differs from current protocols, where the on-field referee is expected to check the monitor for subjective decisions like red cards or penalties. For offside, the system’s objective measurement is considered definitive.

The 2026 World Cup Implementation Roadmap

FIFA has laid out a clear timeline for rolling out the technology. The next major test will be the 2025 FIFA Club World Cup, which will be held in the United States. That tournament will serve as a dry run for the 2026 World Cup, with the same system installed in all 11 host stadiums. FIFA expects to collect data on reliability, calibration, and referee training during that event.

IFAB, the body that sets the laws of the game, is expected to approve the technology by March 2026. The approval is expected to be approved, given that IFAB has already endorsed semi-automated offside technology in principle. However, IFAB may impose conditions, such as requiring a human VAR to be able to override the system in case of a malfunction. UEFA’s trials did not include such an override, but FIFA has indicated that a “safety net” will be in place for the World Cup.

Each of the 16 host venues—10 in the US, three in Mexico, and three in Canada—will need to be wired with the necessary receivers and cameras. The installation cost is estimated at roughly $2 million per stadium, a figure that includes hardware, software, and calibration. FIFA will cover the cost as part of its technology budget for the tournament. The venues already have goal-line technology installed, and the new system can piggyback on that infrastructure in most cases.

Training for match officials will begin in early 2026. Referees will need to learn to trust the system’s automatic calls, which may require a psychological shift. In the UEFA trials, some referees initially wanted to double-check the monitor, but were instructed to rely on the watch alert. By the end of the trial, acceptance was high. The next step is to ensure that all 48 match referees at the World Cup are comfortable with the technology.

Trade-Offs: Accuracy vs. Speed in Marginal Offside Calls

Speed is not the only metric that matters. Accuracy is paramount, especially in a World Cup where a single goal can decide a knockout tie. UEFA reported a 98.7% accuracy rate in the trials, meaning that roughly 1.3% of offside decisions were incorrect or required a second look. That is better than the 2022 system, which had an accuracy of roughly 96%, but still leaves room for error.

Marginal offsides remain a challenge. Those where the attacker’s toe or heel is a few centimeters beyond the defender’s line. The ball chip’s 1.5 cm margin means that calls within that threshold are inherently uncertain. In practice, the system will flag any offside where the attacker’s torso is ahead of the defender’s torso, even if the margin is smaller than the chip’s error window. This could lead to goals being disallowed for offsides that are not reliably measurable.

Critics have raised the concern that the system might over-correct for speed. In the chase for a nine-second review, the algorithm might prioritize a quick decision over a careful one. UEFA’s data suggests this is not the case: the system only renders a decision when it has a clear measurement. If the ball chip signal is lost or the cameras are blocked, the system defaults to a “no decision” state, and the VAR manually reviews the footage. This happened in roughly 2% of incidents during the trial.

Some former players and pundits have argued that the game should accept a degree of uncertainty in offside calls, and that the obsession with millimetric precision ruins the spectacle. The new system does not solve that philosophical debate. It simply makes the decision faster. Whether that is a net positive depends on whether fans prefer a quick, imperfect call or a slower, more accurate one. The 2026 World Cup will be the ultimate test.

In-Stadium and Broadcast Experience Will Change

For fans in the stadium, the most visible change will be the disappearance of the long wait. When a goal is scored, the referee’s watch will vibrate within seconds. If the goal is onside, the referee will point to the center circle and the game resumes. If offside, he will raise his arm. The big screen will show a 3D replay of the offside decision before the next kick-off, giving fans a clear explanation.

Broadcasters will also adapt. Currently, TV directors cut to a graphic that shows lines being drawn, often taking 20 to 30 seconds of airtime. With the new system, the graphic can be ready in under 10 seconds. Commentators will have the decision before they have finished describing the goal. This should reduce the awkward silence that currently fills the air while the VAR checks.

The change could also affect the length of matches. In the 2022 World Cup, the average stoppage time per half was roughly 10 minutes, partly due to VAR reviews. If offside checks are reduced from 48 seconds to 9, the cumulative time saved could be significant. However, other delays—like substitutions, injuries, and goal celebrations—will remain. The net effect on total match duration may be modest.

The speed may reduce the suspense some fans enjoy. Some fans enjoy the tension of the VAR check, the slow-motion replays, and the eventual reveal. The new system removes that suspense. Whether that is a loss or a gain is subjective. What is clear is that the in-stadium experience will be more immediate, and that the referee will be empowered to make decisions without external pressure.

What Still Needs to Be Solved Before 2026

Despite the promising trials, several technical and logistical hurdles remain. The ball chip’s battery life is one concern. The chip must last for the full 90 minutes plus extra time and penalties. In the UEFA trials, the chip had a battery life of roughly four hours, which is adequate. But FIFA will need to ensure that the chips are fresh for every match and that they can be replaced quickly if they fail.

Signal interference is another issue. Large stadiums with 85,000 or more spectators can generate electromagnetic noise from mobile phones, Wi-Fi, and broadcast equipment. The UWB signal used by the Kinexon chip is designed to be robust, but it has not been tested in the largest venues. FIFA plans to conduct interference tests in all 16 host stadiums before the tournament.

Protocol issues also need resolution. For example, what happens if the system fails to detect a kick point because the ball is obscured? The current protocol calls for a manual review, but that could take longer than the promised 10 seconds. FIFA must decide whether to allow a longer review in such cases or to accept a default “onside” call. The latter would be controversial if it leads to a goal that should have been disallowed.

Finally, referee training is crucial. The system removes the need for the assistant referee to raise his flag immediately, but the assistant must still be ready to signal if the system malfunctions. Referees will need to practice trusting the technology, especially in high-pressure moments. The 2025 Club World Cup will be the first real test of that trust. If it goes smoothly, the 2026 World Cup could mark the end of the VAR delay era.