Polymarket vs sportsbooks: how prediction-market odds compare
Polymarket prices sports outcomes as tradable shares instead of odds. Under the hood it is the same question — how likely is each side? — answered by an order book of traders rather than a bookmaker. Here is how to read it and how it stacks up against sportsbook lines.
Cents are probabilities
Each outcome trades as a share that settles at $1 if it happens and $0 if not. So the price is the probability: 62¢ means the market thinks 62%. You can buy, and you can sell before the game ends if the price moves.
| Polymarket price | Implied | American | Decimal |
|---|---|---|---|
| 25¢ | 25% | +300 | 4.00 |
| 40¢ | 40% | +150 | 2.50 |
| 50¢ | 50% | +100 | 2.00 |
| 62¢ | 62% | −163 | 1.61 |
| 75¢ | 75% | −300 | 1.33 |
Use the odds converter with the “Probability” input to convert any price.
How it differs from a sportsbook
| Sportsbook | Polymarket | |
|---|---|---|
| Who sets the price | The book’s traders | Buyers and sellers in an order book |
| The margin | Vig built into both sides, often 4–5% on main lines | Bid/ask spread, plus a taker fee (sports: 0.05; Polymarket US: 0.0695) |
| Limits | Set by the book, can be cut for winning players | Whatever depth is resting in the book |
| Cash out | At the book’s cash-out price, if offered | Sell shares at the market price |
| US access | Licensed state by state | International exchange blocks US traders; separate US platform |
Spread, depth and the no-vig price
If Team A’s shares cost 52¢ and Team B’s cost 50¢, buying both costs 102¢ for a guaranteed $1 — a 2% “overround”, just like a book’s vig, created by the bid/ask spread. In a tight, deep market the midpoint is a sharp estimate of the no-vig price. In a thin one a few hundred dollars can push the price around, so the quoted cents may not be available in any size.
Fees: the price you actually pay
Buying at the ask is a taker trade, and both exchanges charge it a fee of rate × shares × price × (1 − price), largest at 50¢. Polymarket’s sports rate is 0.05 (since 2026-07), taken in shares on a buy, so you receive slightly fewer. Polymarket US charges 0.0695 (since 2026-09-25), rounded to the cent.
100 shares at 50¢: Polymarket $1.25 · Polymarket US $1.74 · $100 at 50¢ after fees: −105 / −107
So a 62¢ favorite is not −163 to a buyer: after the fee it is −172 on Polymarket and −175 on Polymarket US. Compare that number, not the raw cents, with a sportsbook price.
When the two disagree
A gap between Polymarket and the books usually means one side has not caught up with news yet, or the exchange is thin. Before acting on it, check the depth and whether sharp books agree. Prediction-market access and legality are changing quickly in the US; follow the rules where you live, and remember that neither market guarantees a profit.
Next: Kalshi sports odds explained.
Frequently asked questions
How do Polymarket odds work?
Polymarket lists shares that pay $1 if an outcome happens and $0 if it does not. The price in cents is the market’s implied probability: a share trading at 62¢ implies about a 62% chance, roughly −163 in American odds.
How do I convert a Polymarket price to American odds?
Treat the price as a probability. Above 50¢: −(price ÷ (100 − price)) × 100, so 62¢ is about −163. Below 50¢: ((100 − price) ÷ price) × 100, so 40¢ is +150. 50¢ is even money (+100).
Can people in the US use Polymarket?
Polymarket’s main international exchange does not accept US traders. A separate US platform operating under CFTC oversight has been rolling out with its own order book and its own rules. Check what is available to you where you live.
Are Polymarket prices more accurate than sportsbooks?
Not automatically. Deep, actively traded markets can be as sharp as the best books, while thin markets can sit on stale or lopsided prices. Order-book depth is the best guide to how much weight a price deserves.
Is there vig on Polymarket?
There is no bookmaker margin, but the bid/ask spread works like one, and both exchanges charge takers a fee of rate × shares × price × (1 − price): 0.05 on Polymarket sports, 0.0695 on Polymarket US. At 50¢ that is $1.25 and $1.74 per 100 shares. The midpoint of a tight market is still a good estimate of the no-vig price.
Live odds boards: NFL odds · NCAAF odds · NBA odds · NCAAB odds · NHL odds · MLB odds · WNBA odds · MMA odds · Cricket odds · EPL odds · MLS odds · UCL odds · Liga MX odds · La Liga odds · Serie A odds · Bundesliga odds · Ligue 1 odds · ATP odds · WTA odds
21+ | Gambling problem? Call 1-800-GAMBLER. Nothing here is betting advice, and no bet or strategy guarantees a profit. Sports betting is legal only in some US states; check the rules where you are. Responsible gambling.