Know your number.
Then make your move.
Three free tools. The math behind every answer. Build a repeatable process before you put a dollar on the line.
Devig calculator
Enter every mutually exclusive outcome from the same book, market, and moment. A single price is not enough to remove the vig.
Includes pushes only if quoted as a separate outcome. For standard two-way markets with refunded pushes, estimates are conditional on no push.
A market-based estimate, not the true chance of winning. Different margin assumptions give different answers.
Show the math
Implied probability = 1 ÷ decimal odds.
No-vig probability = outcome’s implied probability ÷ sum of all implied probabilities.
Overround = sum of implied probabilities − 1. Fair decimal odds = 1 ÷ no-vig probability.
Learn it. Check it. Track it.
Start with a lesson, compare the live prices, then judge the full record.