What are fair odds?

Every sportsbook price includes a built-in margin, sometimes called the vig or the juice. It's how the book makes money regardless of the outcome. That margin means the odds you see are always slightly worse for you than the sportsbook's own estimate of the true probability.

What "fair" means here

Fair odds are what a market would look like with that margin removed. Take a two-sided market, like a moneyline. Add up the implied probability of both sides at a single sportsbook and the total is always a bit more than 100%. That extra is the book's margin. Rebalancing both sides back to a true 100% gives you a no-vig, or de-vigged, probability for each side. Convert that probability back into odds format and you have a fair price: a number with no sportsbook markup built in.

Why one book isn't enough

A single sportsbook's de-vigged number is still just one book's opinion. Different books set their opening numbers differently and adjust at different speeds. A more reliable baseline comes from blending de-vigged probabilities across several sportsbooks into a weighted consensus, so no single book's quirks dominate the estimate. That consensus is what we mean when we say "fair odds" on Fair Value Betting.

What fair odds are for

Fair odds aren't a prediction of who wins. They're a reference point. Once you know what a bet should cost in a margin-free market, you can compare it against what a specific sportsbook is actually charging. If the best available price is better than fair, that's what we mean by a positive expected value, or EV%, opportunity. If it's worse, the price is priced against you relative to the market.

What it doesn't mean

• Fair odds are an estimate from the current market, not a guarantee of the true probability.
• The consensus can be wrong, particularly in thin markets with fewer books offering a price.
• A favorable price relative to fair odds does not mean that specific bet will win.