Free betting calculators
A set of free calculators for the maths behind a bet — expected value, staking, arbitrage and bonus-bet value. Each runs entirely in your browser; nothing is stored and no account is needed. They're research and education tools, not betting advice.
Expected value (EV) calculator
Enter decimal odds, your true win probability and stake to see a bet’s expected value in dollars and as a percentage — and whether it’s +EV or −EV.
Kelly criterion calculator
Work out the Kelly-optimal stake from your edge and the price, with fractional-Kelly options to size a bet more conservatively.
Arbitrage (arb) calculator
Check whether two prices across books lock in a profit, and split the stake across both sides so the return is equal whichever way it lands.
Odds converter
Turn decimal, fractional or American odds into every other format and into the implied probability behind them, all at once.
Vig & margin calculator
Enter every price in a market to see the bookmaker’s margin — the overround — and what that market is costing you before you have an opinion.
No-vig (fair odds) calculator
Strip the bookmaker’s margin out of a market to see the fair price and true probability behind each outcome.
Hedge calculator
Work out what to stake on the other side of a bet you already hold, and what you keep either way once both stakes are counted.
Back / lay calculator
Lay stake, liability and commission for a back-and-lay position on an exchange — including when it quietly loses money.
Bonus bet calculator
Estimate the real cash value of a bonus (stake-not-returned) bet and see what price you need to extract the most from it.
Why these tools
Every one of these calculators depends on one honest input: how likely an outcome actually is. Get that right and the maths tells you whether a price is worth taking and how much to stake; get it wrong and no formula can save the bet. That's the problem HaterPicks' graded player-prop models are built to help with — projecting a line and publishing how often the projection hits.
Want honest probabilities to plug in?
HaterPicks projects player-prop lines and grades every pick win or lose. Free trial · no card to start.
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