Odds & probability
Break-Even Calculator
Start with a win probability and find the fair price that breaks even.
How to read your result
The fair price is the odds equivalent of your estimated win probability. It contains no added margin. A higher decimal price offers better value for the same probability estimate.
A 55% win probability corresponds to decimal odds of about 1.818 and American odds of about −122.
Formula and assumptions
Fair decimal odds = 1 ÷ p. If p is below 50%, fair American odds = 100 × (1 − p) ÷ p. At or above 50%, fair American odds = −100 × p ÷ (1 − p). Rounded display values are approximate; use the unrounded probability when evaluating a close price.