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Know the math
behind the odds.
Free calculators for payouts, probabilities and market margins. Change the inputs, follow every step, and share the result. No account required.
Odds calculator
Return = stake × decimal odds. Profit = stake × (decimal odds − 1).
Open calculator →02 / CalculatorParlay calculator
Return = stake × d₁ × d₂ × … × dₙ.
Open calculator →03 / CalculatorOdds converter
Positive American: d = 1 + a/100. Negative American: d = 1 + 100/|a|. Probability = 1/d.
Open calculator →04 / CalculatorImplied probability calculator
Implied probability (%) = 100 ÷ decimal odds.
Open calculator →05 / CalculatorArbitrage calculator
Q = Σ(1/dᵢ). Stakeᵢ = bankroll/(dᵢ × Q). Net = bankroll/Q − bankroll.
Open calculator →06 / CalculatorHedge calculator
Hedge stake = original stake × original decimal odds ÷ hedge decimal odds.
Open calculator →07 / CalculatorNo-vig calculator
pᵢ = 1/dᵢ; S = Σpᵢ. Multiplicative: pᵢ/S. Additive: pᵢ − (S − 1)/n. Power: pᵢᵏ with Σpᵢᵏ = 1. Shin: (√(z² + 4(1 − z)pᵢ²/S) − z)/(2(1 − z)), summed to 1.
Open calculator →08 / CalculatorHold and vig calculator
Overround = Q − 1. Theoretical hold = 1 − 1/Q; Q = Σ(1/d).
Open calculator →09 / CalculatorKelly criterion calculator
Fraction = max(0, (p × d − 1)/(d − 1)) × chosen Kelly fraction.
Open calculator →10 / CalculatorExpected value calculator
EV = stake × (p × d − 1). ROI = p × d − 1.
Open calculator →11 / CalculatorClosing line value calculator
CLV (%) = (taken decimal odds ÷ closing decimal odds − 1) × 100.
Open calculator →12 / CalculatorBonus bet conversion calculator
Cash hedge = bonus × (bonus odds − 1)/hedge odds.
Open calculator →13 / CalculatorRound robin calculator
Bets = n!/(k! × (n − k)!). Total stake = bets × stake per parlay.
Open calculator →14 / CalculatorTeaser calculator
Return = stake × D. Profit = stake × (D − 1). Equal-leg break-even p = D^(−1/n), assuming n independent, equally likely legs and no pushes.
Open calculator →15 / CalculatorSame game parlay calculator
Quoted return = stake × offered D. Independent reference = d₁ × … × dₙ. Price difference (%) = (offered D ÷ reference D − 1) × 100.
Open calculator →Educational models. Inputs are yours; these tools do not supply picks or live prices.