Implied probability is 1 / decimal odds. At -110 (1.909 decimal), the implied probability is 52.38%. Note: implied probabilities across both sides of a market always sum to more than 100% — the excess is the book's vig.
Math & probability
Implied probability
The win probability baked into a given odds line, as a percentage.
Example
-110 implies 52.4%. +150 implies 40%. +100 implies 50%.
Related terms
Vig (juice)
The sportsbook's built-in margin — the reason implied probabilities add up to more than 100%.
No-vig price
The "fair" line after stripping out the book's margin. Best used to sanity-check your edge.
Expected value (EV)
The average profit per bet if you could replay the same situation thousands of times.