Odds converter
American, decimal, fractional and implied probability, all from one number.
Open the calculator : Odds converter6 free calculators
Free sports betting calculators
Fast, accurate calculators for converting odds, removing the vig, and sizing a bet. They run in your browser, with no account and no sign-up. The demos elsewhere on this site use fictional data; these are real math.
No-vig calculator
Strip the bookmaker margin from a two-way market to find the fair price.
Open the calculator : No-vig calculatorExpected value calculator
EV per $100, EV percent and your edge over the price's implied odds.
Open the calculator : Expected value calculatorKelly criterion calculator
Size a stake from the price, your win probability and your bankroll.
Open the calculator : Kelly criterion calculatorArbitrage calculator
Split a stake across two books to lock in a profit, when one exists.
Open the calculator : Arbitrage calculatorParlay calculator
Combine 2 to 8 legs into one price, payout and probability.
Open the calculator : Parlay calculatorNeed this inside your product?
I build odds tools like this for betting startups, data companies and prediction markets, from a single calculator to a full odds screen. You keep the code either way.