A market betting on the total number of goals in a match being above or below a set line — most commonly Over/Under 2.5 goals.
Over/Under is a total goals market. You bet on the combined number of goals scored by both teams in the match going over or under a set line. The .5 format is used to eliminate push bets — Over 2.5 wins if there are 3+ goals total; Under 2.5 wins if there are 0, 1, or 2 goals total.
Common lines: Over/Under 1.5, 2.5, 3.5, and 4.5. The 2.5 line is most popular because it sits closest to the average goals per match in most professional leagues.
Start with each team's average goals scored and conceded per game at their respective venues. Add the home team's goals per home game to the away team's goals per away game, and similarly for goals conceded. A combined expected goals figure well above 2.5 supports an over; well below suggests an under.
The Poisson model is the most robust approach — it takes expected goals inputs and calculates the probability of every scoreline, then sums the relevant probabilities to give you the true Over/Under probability for comparison against bookmaker odds.
BTTS (Both Teams to Score)
A betting market that pays out if both teams score at least one goal in the match, regardless of the final result.
Poisson Distribution
The statistical model used to predict football match scorelines by treating goal-scoring as a random process based on each team's expected goals rate.
xG (Expected Goals)
A metric that scores every shot by its probability of resulting in a goal, based on factors like shot location, angle, and assist type.
Implied Probability
The probability of an outcome embedded in bookmaker odds — calculated by dividing 1 by the decimal odds.
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