How to read Polymarket odds
Updated · 5 min read
A Polymarket price in cents is the market's implied chance. A share priced at 40¢ means about a 40% chance. If it wins, the share pays $1, so you get back 1 ÷ 0.40 = 2.5x what you paid (a profit of 60¢ per share). The lower the price, the bigger the multiplier.
The price is the probability
Every Polymarket outcome trades between $0.00 and $1.00. A winning share is redeemed for $1 and a losing share becomes worthless, so the price you pay is also the market's estimate of the chance it wins: 25¢ means about 25%, 50¢ about 50%, 75¢ about 75%.
Nobody at Polymarket sets these numbers. Prices come from supply and demand as people trade with each other, in the same way a stock price is not set by the stock exchange.
Cents, percentage, multiplier and American odds
The same number can be written in four ways. This table converts a share price into the formats you will see on Polymarket, on Polycord and at sportsbooks:
| Price | Chance | Multiplier (total return) | Profit per $1 share | American odds |
|---|---|---|---|---|
| 10¢ | 10% | 10.00x | 90¢ | +900 |
| 25¢ | 25% | 4.00x | 75¢ | +300 |
| 40¢ | 40% | 2.50x | 60¢ | +150 |
| 50¢ | 50% | 2.00x | 50¢ | +100 |
| 60¢ | 60% | 1.67x | 40¢ | −150 |
| 75¢ | 75% | 1.33x | 25¢ | −300 |
| 90¢ | 90% | 1.11x | 10¢ | −900 |
The formulas are simple: multiplier = 1 ÷ price (this is the same as decimal odds), and chance = price. For American odds, a price below 50¢ gives +((1 − price) ÷ price × 100), and a price above 50¢ gives −(price ÷ (1 − price) × 100).
The price you see vs. the price you pay
The headline price is usually the midpoint between the best price someone will pay (the bid) and the best price someone will sell at (the ask). If the bid is 34¢ and the ask is 40¢, Polymarket shows 37¢, but a buyer pays the ask (40¢) and a seller receives the bid (34¢). When the gap is wider than 10¢, Polymarket shows the last traded price instead.
That gap is called the spread, and it is a real cost. Busy markets have tight spreads; quiet markets can have wide ones. See Polymarket fees explained for the full picture.
Why Yes and No add up to about 100¢
Each pair of Yes and No shares is backed by $1 of collateral, so the two sides always settle to $1 in total. That is why a Yes at 62¢ goes with a No at roughly 38¢. Small gaps appear because of the spread.
Reading a parlay multiplier
For a parlay, multiply the chances of the legs, then invert. Three legs at 70%, 60% and 55% give 0.70 × 0.60 × 0.55 = 0.231, a multiplier of 1 ÷ 0.231 ≈ 4.33x. More on this in how parlays work on Polymarket.
On every Polycord ticket, the percentage next to each leg is its implied chance, the big number is the combined multiplier, and the line below shows what a $10 stake would return.
Common mistakes
- Confusing multiplier and profit. 2.5x means $25 back on $10, not $25 of profit.
- Treating a price as a guarantee. 90¢ is a 90% chance, which still loses one time in ten.
- Ignoring fees and spread. The real payout is a little lower than 1 ÷ price.
- Assuming a cheap price is good value. A low price just means the market thinks the outcome is unlikely. Whether it is a bargain depends on your own view.
Frequently asked questions
Is a 50¢ price a coin flip?
In market terms, yes: it implies about a 50% chance. If it wins, the share pays $1, so you get back 2x what you paid.
How do I convert Polymarket odds to decimal odds?
Divide 1 by the price. A 40¢ share is 1 ÷ 0.40 = 2.50 in decimal odds.
Why don't Yes and No always add up to exactly 100¢?
Each pair is backed by $1, but the displayed price is a midpoint between buyers and sellers, so small gaps (the spread) appear.
What does the percentage on a Polycord ticket mean?
It is the implied chance of that leg, taken from the Polymarket price when the ticket was created. The big multiplier is the product of all legs.