Free tools
Betting calculators
Free calculators for the math that matters: convert odds, strip the vig, price a fair line, size a Kelly stake, check +EV, and work out arbitrage, dutching and hedges.
Odds Converter (Decimal, American, Fractional & More)
Convert between decimal, American, fractional, probability and prediction-market cents.
Open calculatorImplied Probability Calculator (Odds to Percentage)
Turn any odds into the implied probability, and see them in every format.
Open calculatorNo-Vig / Fair Odds Calculator
Strip the bookmaker margin from a market and see the fair odds and true probabilities.
Open calculatorBookmaker Margin Calculator (Overround)
See the margin (overround) a bookmaker builds into a market.
Open calculatorExpected Value (+EV) Calculator
Enter the odds and the true chance to see whether a bet is +EV and by how much.
Open calculatorClosing Line Value (CLV) Calculator
Compare the odds you took against the closing line to see if you beat the market.
Open calculatorKelly Criterion Stake Calculator
Turn your bankroll, odds and edge into an optimal stake with the Kelly criterion.
Open calculatorArbitrage Calculator (Surebet)
Split a stake across bookmakers so every outcome returns the same.
Open calculatorDutching Calculator
Split a stake across selections so you win the same whichever one lands.
Open calculatorHedge Betting Calculator
Bet the other side to lock in a profit or cut a loss on an open bet.
Open calculator