Enter all mutually exclusive outcomes of one complete market. The tool separates the total implied probability from the excess above 100%, known as overround.
Formula and worked example
Implied total = 100 × sum of (1 ÷ each price). Overround = implied total − 100%. Normalized shares sum to 100% but are not independent forecasts of actual outcomes.
Two outcomes priced at 1.90 each imply about 52.632% apiece. The total is 105.263%, so the overround is 5.263 percentage points. Dividing each implied probability by the total gives normalized shares of 50% and 50%.
What the calculation means
Overround approximates the bookmaker margin from quoted prices, not the operator’s guaranteed profit on every event.
A total below 100% is an underround in the entered prices. It does not establish that all prices are available together, cover the same settlement rules or can be acted on.
From a selection to settlementEducational estimates only; no outcome is guaranteed. For adults where lawful. Set limits and never chase losses.
Try another worked scenario
Load an example, then select Calculate. These hypothetical inputs remain editable before calculation.
Implied sum about 105.263%; overround about 5.263 percentage points.
Implied sum about 103.571%; overround about 3.571 percentage points.
Implied sum 100%; overround 0 percentage points.
Use mutually exclusive outcomes that cover the whole same market. Home, draw and away are three outcomes; two team prices alone omit the draw. The displayed overround is not a guaranteed operator profit or a forecast of player loss in one event.