Fair odds are the margin-free version of a market: the prices that would make the book break even in the long run. The simplest way to estimate them is to take every outcome's implied probability, sum them, and scale each one down proportionally so the total equals exactly 100%. The rescaled probabilities convert back into fair odds.
Fair odds matter because they are the benchmark for value. A price only represents value if it exceeds the fair price, not merely if it 'looks big'. Averaging fair probabilities across many bookmakers produces a robust consensus that is hard for any single operator's pricing quirk to distort — this consensus-versus-best-price comparison is exactly how our model flags value picks.
Implied probabilities 47.6% / 27.8% / 29.4% (total 104.8%) rescale to 45.4% / 26.5% / 28.1%. Fair home odds = 1 / 0.454 = 2.20. Any book offering more than 2.20 is paying above the market's own estimate.