Learn sports betting math
Short, worked-through guides to how prices work on Polymarket and at the books, and how to tell a good price from a bad one.
- How to read Polymarket sports odds: What a Polymarket price in cents means, how to turn it into American or decimal odds, and how the spread, depth and fees change what you pay. (3 min)
- Polymarket vs sportsbooks: fees, limits and settlement: How betting a game on Polymarket differs from a sportsbook: who sets the price, what each costs, limits, selling early, and how each settles a result. (2 min)
- Polymarket fees explained for sports bettors: Polymarket’s taker fee formula, the sports rate, why the fee peaks at 50¢, what makers pay, and how fees change your break-even and your odds. (2 min)
- What are no-vig fair odds and how to calculate them: What the vig is, how to remove it to get fair odds, the multiplicative, additive and power methods with worked examples, and how to use a fair line. (2 min)
- Arbitrage betting between Polymarket and sportsbooks: How arbitrage between Polymarket and DraftKings or FanDuel works: the fee math with a worked example, settlement traps, and why most gaps are too small. (2 min)
- Expected value betting, with worked examples: What expected value means in betting, how to calculate it on Polymarket and at the books, where the win chance comes from, and why +EV bets still lose. (2 min)
- Kelly criterion and bankroll sizing for sports bets: How the Kelly criterion sizes a bet from your edge, the growth math behind it, why full Kelly swings so hard, and how fractional Kelly trades growth for safety. (3 min)
- Closing line value: why it predicts long-term profit: What closing line value is, how to measure it on Polymarket and at the books with worked examples, and why beating the close is the best early sign of an edge. (2 min)
- Are parlays ever +EV? Correlation explained: Why parlays compound the vig, worked through leg by leg, the two cases where they can be +EV, and how correlation between same-game legs changes the math. (2 min)
- How to follow Polymarket sports whales: How to find the top Polymarket sports traders, read their records by league, tell skill from size, and judge whether a big trade is still worth following. (1 min)
- How AI sports models price games: What goes into a sports betting model: market consensus, team ratings and calibration, the math of pooling and scoring, what AI adds, and how to check a model. (2 min)
- Can you use Polymarket for sports in the US?: A neutral overview of how Polymarket operates for US users, how sports event contracts are regulated, and what to check before you trade. (2 min)
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