NinetyFootball guides
Plain-English answers to the football questions people search for: expected goals, the offside rule, how leagues and the Champions League work, how win probability is calculated and more.
What is xG (expected goals)?
xG measures the quality of a shot as the chance it becomes a goal. How it is calculated, how to read it, and why it predicts results better than shots alone.
What are expected points (xPts)?
Expected points turn a match’s chances into the points a team deserved. How xPts is worked out and what a big gap against the real table tells you.
How football win probability works
How to turn football odds into a win probability, why the numbers add to more than 100%, and how prediction markets and models compare.
How the Champions League format works
How the Champions League works: the 36-team league phase, the top eight, the play-offs and the knockout rounds, in plain words.
How football leagues work: points, promotion and relegation
How a football league season works: points, the table, promotion and relegation, and how the top European leagues differ.
How these guides are written
Each guide answers one question the way you would explain it to a friend at the match: the answer first, then a worked example with real numbers, then where the idea stops being reliable. We only publish things that do not go out of date at the end of the season. Anything that changes every year, such as a league table or a fixture list, lives on the live pages instead: see the competition pages for tables and results, or the fixtures for what is on today.
The statistics guides pair with the free calculators, so you can put your own numbers into the same maths. If a guide has an error or leaves out something you wanted, email [email protected] and we will fix it and note the date on the page.
