🎲 How to read Polymarket odds — prices are probabilities

Polymarket doesn't quote odds — it quotes prices, and the price is the probability. A YES share trading at 65¢ means the market collectively prices about a 65% chance of that outcome. No conversion tables, no bookmaker formats: read the cents, and you've read the market's forecast. This page covers the payoff math that follows from that, and the things a price does not tell you.

Cents to probability, in one step

Because a winning share redeems for exactly $1, its price is the market's probability estimate expressed in cents:

The pattern: profit if right = 100¢ − price; loss if wrong = price (before the 1% trading fee). Long shots pay a lot precisely because the market thinks they rarely happen; favorites pay little because they usually do. Neither is inherently "better value" — the price already reflects the market's estimate of how often each side wins.

YES and NO are two views of one question

In a binary market the two sides sum to about $1: YES at 65¢ implies NO around 35¢. Buying NO at 35¢ is the position "this won't happen" — it redeems at $1 if the event fails. So there's never a need to "bet against" anything in a special way; you just buy the other side. (The sum can drift a little from exactly $1 with the spread in each book.)

Prices move — that's the point

A prediction market price is a live estimate, updated continuously as traders react to news. A market that opened at 30¢ can be at 60¢ a week later, and back at 40¢ the week after. Two consequences:

• Your entry price is what defines your bet. Buying YES at 30¢ and buying YES at 60¢ are very different trades on the same market.
• The chart tells a story. A price drifting up on rising volume reads differently from a spike on one headline. Watching how a market got to its price is part of reading it.

You can sell before the end

You are not locked in until resolution. A position can usually be sold at any time at the current market price, subject to liquidity: bought at 30¢ and the price is now 60¢? You can sell and realize the difference without waiting for the event. Price moving against you? You can cut the position — at a loss — instead of riding it to $0. This is the core difference from a betting slip, covered in Prediction markets vs betting.

What a price does not tell you

• It's not a guarantee. A 70¢ outcome carries an implied 30% chance of failing — and 30% events happen all the time. Holding to resolution means accepting the full $1-or-$0 outcome.
• Thin markets are noisy. In a low-volume market, one modest order can move the price several cents; the "probability" you read may be a few traders' opinion, not a crowd's. Check volume and the order book before treating a price as a forecast.
• It doesn't know why. The price aggregates opinions; it doesn't tell you the reasoning. The market's resolution rules — what exactly counts as YES, and how it resolves — matter as much as the number.

Positions can lose part or all of their value; this page is informational only and is not investment advice — see Legal notes.

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