Implied Probability & Vig Removal

Convert odds to implied probability, and strip the bookmaker's overround to get the fair line.

Single odds → probability

Two-way market — remove vig

Implied probability
52.36%
Decimal 1.91

Vig-removed (fair) probabilities

LegImpliedFair
A52.36%50.00%
B52.36%50.00%

Overround: 4.71% — the book's expected margin over a balanced market.