Over 2.5 and both teams to score (BTTS) explained

Over 2.5 means three or more goals in the match; under 2.5 means two or fewer. Both teams to score (BTTS) – yes means each side scores at least once.

Over/under 2.5 probability

This comes directly from world-market over/under prices. The margin is removed from each bookmaker's pair of odds and the remaining probabilities are averaged.

BTTS probability: the Poisson model

Because too few bookmakers price BTTS on every match, harbigol calculates it. Goal counts in football fit a Poisson distribution well. First the total expected goals are derived from the over 2.5 probability – for example, 50% corresponds to about 2.67 goals. That expectation is then split between the two teams so that it matches the match-result probabilities. Finally, the chance of both teams scoring is (1 − e^−λhome) × (1 − e^−λaway).

For a match with expected goals of 1.5 and 1.1, BTTS-yes is about (1 − 0.223) × (1 − 0.333) ≈ 51.8%. These values are marked “calculated” on the site and in our posts.

A model is a simplification of reality; probabilities are not guarantees.