Definition
Fair odds (also called no-vig odds or true odds) are the theoretical odds of an event if the bookmaker took zero margin. They represent the genuine probability estimated by the market. Knowing fair odds lets you identify value bets and objectively compare offerings across bookmakers.
How It Works
Bookmaker odds always include a built-in margin (vig). To find fair odds, you remove that margin. The simplest method (multiplicative): calculate the sum of implied probabilities S = 1/Odds_A + 1/Odds_B, then for each outcome, Fair Odds = Displayed Odds x S. Any bookmaker offering odds above the fair price on an outcome is giving you a value bet.
Example
Tennis match, displayed odds: Player A 1.80 / Player B 2.10
- Implied probabilities: 1/1.80 + 1/2.10 = 0.556 + 0.476 = 1.032 (margin = 3.2%)
- Fair odds A: 1.80 x 1.032 = 1.858
- Fair odds B: 2.10 x 1.032 = 2.167
If another bookmaker offers Player B at 2.25, that is a value bet since 2.25 > 2.167 fair odds.
Why It Matters
Fair odds are your benchmark for every bet. They let you identify value bets (any odds above fair price), compare bookmaker competitiveness, and estimate true market probabilities. Without understanding fair odds, you are essentially betting blind -- you have no way to know whether the price you are getting is good or bad.
Use our no-vig calculator to instantly strip the bookmaker's margin and discover the true probability of each outcome.