Odds Calculator
Convert between American, decimal, and fractional odds, and see implied probability and payout on any stake — instantly, nothing sent anywhere.
Not sure what these numbers mean yet? Start with our guide to how odds work — it walks through American, decimal, and fractional formats from scratch, including how implied probability and the sportsbook's vig fit in.
Frequently asked questions
Does this calculator store or send my odds anywhere?
No. All the math runs directly in your browser with plain JavaScript — nothing is sent to a server, logged, or tracked.
Why does implied probability add up to more than 100% on a real matchup?
Because sportsbook odds include the vig (the book's built-in margin) on both sides of a bet. This calculator shows the implied probability of the single odds you enter, not a two-sided matchup — see our odds guide for how the vig works.
Which odds format should I use day to day?
Whichever your sportsbook displays by default — usually American in the US. This tool exists for the moments you need to compare against a decimal or fractional line from another source.