Free betting tools
Free Sports Betting Calculators
15 professional-grade tools, the same math sharp bettors use, free with OddsGuard.
Compare odds, size bets, strip vig, build parlays, and convert prediction market prices. Every calculator runs locally in your browser and shares the same engine we ship in our apps and extension.
Arbitrage
Calculate hedge stakes across two outcomes to lock in profit when books disagree.
Open calculatorExpected Value
Measure whether a bet beats the book over the long run using your fair win probability.
Open calculatorBonus Bet
Convert free plays and bonus bets into cash-equivalent profit with an optimal hedge.
Open calculatorHalf Point
Compare fair prices when buying or selling a half point on spreads and totals.
Open calculatorHold
Find the sportsbook margin on a two-way market from both sides of the line.
Open calculatorImplied Probability
Convert between odds formats and implied probability with live payout math.
Open calculatorKelly
Size bets optimally from your edge, odds, and bankroll using fractional Kelly.
Open calculatorNo-Vig Fair Odds
Remove the juice from both sides of a market to reveal fair win probabilities.
Open calculatorOdds Converter
Switch between American, decimal, fractional odds and implied probability instantly.
Open calculatorParlay
Combine multiple legs into one parlay with combined odds, profit, and payout.
Open calculatorPrediction Markets
Convert Polymarket-style prices (0 to 100 cents) to sportsbook odds and back.
Open calculatorPoint Spread
Compare spread and moneyline value using historical fair-price relationships.
Open calculatorPoisson
Model prop and counting markets with Poisson probabilities and fair odds.
Open calculatorRound Robin
Build round robin parlays, count combinations, and simulate outcomes by leg.
Open calculatorVig
Calculate sportsbook vig / juice on a two-way market from both posted odds.
Open calculatorStop Leaving Money on the Table
Same Bets. Better Prices. Found Instantly.
The same 4-leg parlay can pay $10,000s more at a different sportsbook. OddsGuard finds the best price across 75 books in real time — replacing tools that charge $200–$600/month.
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