How We Compute Fair Betting Odds, Holds and the Scoreline Model

The hold

For any market, sum the reciprocals of the decimal prices. A fair market sums to exactly 1; whatever exceeds 1 is the bookmaker's theoretical hold. Two prices of 1.875 and 1.925 sum to 1.0528 - a 5.28% hold. We badge every market with it so you can see at a glance which of a match's markets is priced sharpest; combination markets (result plus total) always carry more, because combining variables compounds the edge.

Fair probabilities and fair odds

Dividing each price's reciprocal by that sum removes the margin proportionally, giving the fair chance the market implies for each outcome - and 1 divided by that chance is the fair price. One property worth understanding: because margin removal only ever raises prices, a book price can never beat its own market's fair price. Fair odds are a yardstick for what the margin costs you, not a value detector.

The scoreline model

We fit a Poisson model to the board itself: total expected goals from the main goals line's fair under-probability, split between the teams so the model reproduces the board's fair three-way match odds. That yields a probability for every scoreline - the heat map - plus derived fair values for markets the snapshot doesn't contain, like draw no bet and double chance. The model knows nothing the board doesn't; it is the board, restated as goals.

The coherence check

The one honest cross-check this allows: the model's both-teams-to-score probability versus the BTTS market's own fair price. When they agree within a couple of points, the board is internally consistent. When they split wider, the totals and the BTTS market are telling different stories - we flag it as information, never as a tip, because a model fitted to a board holds no edge over that board.

Snapshots and archiving

Boards are captured manually and timestamped; prices move, so always check current odds before betting. When a match finishes, its page stays at the same URL permanently: the final snapshot is frozen, each market is graded against the result, and the page becomes a historical closing-odds reference.