Odds basics
- What does +150 mean? — American odds for an underdog, what your $10 bet pays, and the implied probability behind the number.
- What does −110 mean? — the standard sportsbook juice line, why it's everywhere, and how much edge the book is taking.
- How to calculate implied probability — converting any odds format into a percentage chance, plus the standard formulas.
Parlays and combinations
- How much does a $10 parlay pay? — payout math for 2-, 3-, 4-, and 5-leg parlays at common odds.
- What is a round robin bet? — splitting a 4- or 5-leg ticket into every smaller parlay combination, and why some bettors prefer it.
- How to hedge a parlay — when your last leg is alive, the math for locking in profit by betting the other side.
Finding and sizing your edge
- How to remove vig from odds — what the sportsbook's hold is, and how to back it out to find the "fair" implied probability.
- What is Kelly staking? — the formula for sizing bets based on your edge, plus why most bettors use half- or quarter-Kelly.
Prediction markets (Kalshi & Polymarket)
- Kalshi cents to odds — how a contract price in cents maps to implied probability and American/decimal odds.
- Prediction markets vs sportsbooks — where the house edge comes from: vig baked into the price vs an explicit per-trade fee.
Also useful
- Glossary — 37 sports betting terms in plain English, with examples.
- All six calculators — Bet, Parlay, Round Robin, EV & Kelly, Arbitrage, No-Vig.
- Responsible gambling — resources if betting is becoming a problem.