What is xG? Expected goals explained for football fans

You will see it on broadcasts, in match reports and across social media: xG, or *expected goals*. It has become the headline number of football analytics. Here is what it means and how to use it without overthinking it.

The one-sentence definition

xG measures the quality of a chance as a number between 0 and 1 — the probability that an average player would score from that situation.

A tap-in from two yards might be worth 0.9 xG (scored nine times out of ten). A speculative effort from 30 yards might be 0.03 xG (scored three times in a hundred). Add up every chance a team creates in a match and you get their total xG for the game.

What goes into the number

xG models are built from hundreds of thousands of historical shots. For each chance, they weigh factors such as:

• Distance from goal
• Angle to the goal
• Body part used (foot vs header)
• Type of assist — a through ball, a cross, a cut-back
• Whether it was a fast break or set piece

The model compares the new chance to all the similar ones it has seen and outputs the historical scoring rate.

How to read xG sensibly

The most useful comparison is goals vs xG over time:

• A team scoring well above its xG for months may be finishing brilliantly — or riding luck that will fade.
• A team scoring below its xG is creating good chances but not converting; results often improve as that gap closes.

In a single match, xG tells you who created the better chances, which is not always the same as who won. A 1–0 win on 0.4 xG against 2.1 xG suggests the winners rode their luck.

What xG is not

xG is a guide, not a verdict. It does not capture a defender's positioning, a goalkeeper's brilliance, or the pressure of a derby. A penalty is fixed at about 0.79 xG regardless of who takes it. Treat xG as one lens among many — powerful for spotting trends over a season, far blunter for explaining a single 90 minutes.

Want to see the underlying results for yourself? Browse recent match centres and scorelines and judge the chances against the final numbers.