Free betting tools

Fast, private calculators. Everything runs in your browser; nothing you type is sent anywhere.

Odds converter

Convert American, decimal and fractional odds, plus the implied probability, in one box.

What chance does a price imply? Turn any odds into an implied probability, and back.

Remove the bookmaker's margin from a two-way market to see the fair odds and fair probability of each side.

How much margin is a book taking on a market? Enter every side's odds to see the hold.

Split a stake across two books so both outcomes return about the same amount, at the prices you enter.

Combine the legs of a parlay to see its total odds, payout and implied probability.

A stake-sizing formula: given your own probability estimate and the price, how much of a bankroll does Kelly suggest?