Free betting calculators
Updated
Calculators for the math behind promotions and price comparisons: lock a profit across two venues, convert a bonus bet, take the vig out of a market, convert odds formats or value a profit boost. They use the same formulas as the SlateProof engine, and none of them places a bet.
All calculators
Arbitrage calculator
Enter prices and a total stake for exact bet sizes and locked profit, net of Kalshi, Polymarket US and ProphetX fees. Formulas and what can void it shown.
Bonus bet calculator
Enter your bonus bet, its odds and the opposite side's odds to get the hedge stake, locked profit and conversion rate, with exchange fees included.
Hedge calculator
Find the hedge stake that locks a profit or limits a loss on an open bet. Equal-profit and partial hedges, sportsbook or exchange prices, fees included.
No-vig calculator
Remove the sportsbook margin with power, multiplicative, additive or Shin methods. See fair probability, odds and vig for two- and three-way markets.
Odds converter
Convert American, decimal and fractional odds to implied probability and back, including Kalshi and Polymarket contract prices in cents. Free and instant.
Profit boost calculator
Enter the odds, boost percent, max wager and extra-winnings cap to see the boosted payout and expected value against fair odds, unhedged or hedged.
Keep going
Each calculator has a guide that explains when the result can be trusted. See also the guides, state-by-state availability, sportsbooks and exchanges, or open the live dashboard for today’s promo plays and arbitrage.