Odds Converter — American ↔ Decimal ↔ Implied Probability
Convert between American odds (used at every NY-licensed sportsbook), decimal odds (used at most European-licensed offshore brands), and implied probability (the true win probability the odds suggest).
Edit any of the three fields; the other two update automatically.
Parlay Calculator
Multi-leg parlay payout calculator. Enter the American odds for each leg, the stake, and the calculator returns the combined odds, payout, and profit. Add or remove legs as needed.
Hedge Calculator
Hedging means placing a wager on the opposite side of an open position to lock in a guaranteed profit (or limit loss). Useful when a futures bet is alive but you want to lock in some value before the outcome. Enter your original stake, original odds, and the current odds on the opposite side — the calculator returns the hedge stake needed to equalize payouts and your guaranteed profit.
Kelly Criterion Bet Sizing
The Kelly criterion calculates the optimal fraction of your bankroll to wager on each opportunity, given your estimated win probability and the odds offered. We display full-Kelly, half-Kelly, and quarter-Kelly sizing. Most experienced bettors use half-Kelly to reduce variance — see our Kelly guide for the deeper analysis.
No-Vig (Fair Odds) Calculator
The "no-vig" or "fair odds" calculator strips the bookmaker's hold from a two-way market to show the true implied probabilities. Useful for comparing offered odds against your own probability estimates. Hold percentage shows how much the operator is keeping; lower hold means better value for bettors.
How to Use These Tools
Three workflows that the calculators above enable:
- Line shopping before a wager. Use the no-vig calculator on each operator's offered odds for a market. The book with the lowest hold percentage is offering the best price. Confirm against the odds converter to ensure you're reading the American odds correctly.
- Sizing a NY sportsbook welcome bonus qualifying wager. Use the Kelly calculator with your bankroll and the qualifying wager's odds. For most welcome bonuses (FanDuel's bet $5 get $300, etc.), full-Kelly aggression is justified because the bonus has heavily positive expected value — the wager itself is essentially break-even and the bonus credit is the real prize.
- Building a same-game parlay. Use the parlay calculator to see the combined odds and payout. Note that operators' actual SGP pricing is meaningfully different from straight-parlay math — they correlate-adjust to reduce payouts on correlated legs. Use the parlay calc for vanilla multi-game parlays; for SGPs, trust the operator's posted price.
For the math behind each tool, see our deeper guides: understanding vig & odds and Kelly criterion bankroll management. For the current best NY sportsbooks to use these calculations at, see the sports betting hub.
Privacy: These calculators run entirely in your browser. No values are sent to a server. No data is logged. Closing the page wipes all calculated values.