If you know the probability and want to convert to odds, the relationship is as follows:


"Odds-1" = (1/Probability) - 1


If your hand has a 25% chance to win, its fair odds are 3-1, because 25% = .25 and 1/.25 = 4 and 4-1 = 3. If a hand has a 10% chance to win, its fair odds are 9-1.