What a fair price is
A fair price is the price at which a bet breaks even exactly, with no margin for anyone. If a team truly wins 60% of the time, its fair price is the one whose payout balances those wins against the 40% of losses: −150 in American odds, 1.667 in decimal.
Sportsbooks never offer fair prices — their margin is built in. But knowing the fair price tells you how far any real price sits from it.
From a probability to a fair price
Decimal fair odds are simply 1 ÷ probability. A 40% chance gives 2.50.
For American odds: if the probability is 50% or more, fair price = −100 × p ÷ (1 − p). At 60%, that is −100 × 0.6 ÷ 0.4 = −150. If the probability is below 50%, fair price = +100 × (1 − p) ÷ p. At 40%, that is +100 × 0.6 ÷ 0.4 = +150.
No-vig prices from a market
You can also find the fair price the market itself implies. Convert each side of the market to an implied probability, add them up, and divide each one by the total to remove the margin. Then convert those no-vig probabilities back into prices.
Example: a game priced −130 and +110. The implied probabilities are 56.5% and 47.6%, adding up to 104.1%. Dividing each by 104.1% gives 54.3% and 45.7% — no-vig prices of about −119 and +119.
The model's fair price
On the SharpDeck board, the Fair column is the model's win probability expressed as a price. It is an opinion, not an offer: you cannot bet it anywhere. Beside it, the Best column shows the best price actually available across the sportsbooks SharpDeck reads, with the book named and stale quotes excluded.
The gap between Fair and Best is the edge. When the best available price pays more than the model's fair price, the price is generous relative to the forecast. When it pays less, it is short.
Why shopping prices matters
The same bet can be priced differently at different books. On a 55% outcome, the difference between +100 and −110 is the difference between a positive and a negative expected value. Comparing the best price against a fair price, rather than accepting the first quote, is one of the simplest habits in disciplined betting analysis.
SharpDeck field notes. Product explanations and worked examples, not betting recommendations.