Fair odds are the odds a match would trade at if nobody took a cut: the true probability of an outcome, expressed as a price. If a team really wins a match 50% of the time, its fair odds are 2.00 — one divided by the probability. Anything below 2.00 is worse than the truth; anything above it pays more than the risk you are taking.
Bookmakers never quote fair odds. They shade every price downwards so that the implied probabilities of all outcomes add up to more than 100% — that extra slice is their margin. A typical 1X2 market at a recreational bookmaker adds up to 104–107%, which means the average bettor is paying 4–7% for the privilege of betting.
To estimate fair odds you need two things: a price source that is hard to beat, and a way to strip the margin out. We use the sharpest market available — bookmakers who welcome winners and let large stakes shape their prices — and remove the margin mathematically (devigging). The result is our best estimate of the true probability of every outcome.
Every number on TipsAudit starts from this estimate. A prediction is not "who we think wins" — it is the outcome the margin-free market considers most likely. And a value flag is never a hunch — it is a soft bookmaker quoting a price above our fair estimate.
See how we apply this on every match in our methodology. Methodology →
Convert each price to an implied probability (1 divided by the decimal odds), remove the bookmaker's margin so the probabilities sum to 100% — we use a power devig, which takes more margin off longshots than a simple proportional split — then convert back: fair odds = 1 divided by the fair probability.
Sharp, low-margin bookmakers such as Pinnacle and betting exchanges are the closest public reference, which is why we benchmark against them. Our measured margin index ranks every bookmaker we track by how far its prices sit from fair.
Bookmaker margin (vig) and devigging Value bet Sharp vs soft bookmakers
See these ideas at work in our public track record — every call logged before kick-off, losses included.