Glossary

What is the difference between fair odds and market odds?

Last updated 2026-07-04

Market odds are the prices books actually offer, vig included. Fair odds are the estimate of what prices would be with no margin and no book positioning: the true probability expressed as a price. Value betting is the discipline of betting market odds that beat fair odds.

Fair odds can come from two sources: devigging a trustworthy market (letting the sharpest books define truth) or from your own model. Market-derived fair odds are humble and robust; model-derived fair odds are where real edges live but also where overconfidence compounds fastest.

The comparison is mechanical once you have both numbers: fair probability 50%, offered price +110 (47.6% implied) means 2.4 points of edge before vig on your exit. Small edges at scale, with discipline about limits and variance, is the entire professional model.

A consensus of 30-50 books anchored on sharp ones is the strongest market-derived fair number available via API: /intelligence/fair-odds serves it precomputed, and the value bets guide walks the full workflow end to end.

Compute it with the API

curl "https://api.theoddsapi.com/intelligence/value?sport_key=basketball_nba" \
  -H "x-api-key: YOUR_API_KEY"

The value endpoint precomputes offered-vs-fair gaps across the slate. Business tier. Free key in minutes.