🧮 Odds, devig, EV & Kelly calculator
Free tools for bettors. Strip the bookmaker margin to get the fair odds, measure your edge and expected value, and size your stake with the Kelly criterion. Everything is computed locally — nothing is sent to any server.
⚽ Score & fair-lines calculator (Poisson) → · 📉 Bankroll & risk-of-ruin simulator →
Remove the margin (devig) → fair odds
Enter the decimal odds of a market. Leave "Draw" at 0 for 2-way markets.
| Outcome | Implied prob. | Fair prob. | Fair odds |
|---|---|---|---|
| Home | 47.6% | 45.4% | 2.20 |
| Draw | 29.4% | 28.1% | 3.56 |
| Away | 27.8% | 26.5% | 3.77 |
Expected value (EV) & Kelly stake
Your "true" probability vs the odds you're offered. Edge is measured against the implied odds.
Stake uses fractional Kelly capped at 5% of bankroll. Informational only — not betting advice. Gamble responsibly (18+).
Parlay
Combine several selections. The true probability per leg is optional — fill them all in to see the parlay's EV.
Parlays multiply the bookmaker margin: even if each leg has only a small edge against you, combining them usually yields negative EV. Fill in the true probabilities to check.
Odds converter
Arbitrage / surebet
Odds of the opposing outcomes of a market (at different books). Leave "C" at 0 for 2-way.
If the sum of implied probabilities is below 100%, splitting the stake this way wins the same amount whatever the result.
Hedge (cash-out)
You have a back bet; cover the opposite outcome to lock in the same net whatever happens.
Closing line value (CLV)
Did you get better odds than the close? Positive CLV is the best indicator of long-term edge (reference: Pinnacle).