Prices Are Probabilities
Every share on Polymarket is priced between$0.00 and $1.00. The price directly represents the market’s belief in the probability of that outcome.
| Price | Implied Probability |
|---|---|
| $0.25 | 25% chance |
| $0.50 | 50% chance |
| $0.75 | 75% chance |
The displayed price is the midpoint of the bid-ask spread. If the spread
is wider than $0.10, the last traded price is shown instead.
Example
If the best bid for “Yes” is$0.34 and the best ask is $0.40:
$0.37—you’ll pay the ask ($0.40) when buying or receive the bid ($0.34) when selling.
The Order Book
The order book is a list of all open buy and sell orders for a market. It has two sides:| Side | Description |
|---|---|
| Bids | Buy orders—the highest prices traders are willing to pay |
| Asks | Sell orders—the lowest prices traders are willing to accept |
Order Types
Market Orders
Execute immediately at the best available price. Use when you want instant execution and are willing to pay the spread.- Buying: You pay the lowest ask price
- Selling: You receive the highest bid price
Limit Orders
Execute only at your specified price or better. Use when you want price control and are willing to wait.- Your order sits in the book until someone trades against it
- Orders can partially fill as different traders match portions of your order
- You can cancel unfilled orders at any time
All orders on Polymarket are technically limit orders. A “market order” is
simply a limit order priced to execute immediately against resting orders.
How Trades Work
Polymarket’s CLOB is hybrid-decentralized:- Offchain matching — An operator matches compatible orders
- Onchain settlement — Matched trades settle via smart contracts
Price Discovery
When a new market launches, there’s no initial price. The first price emerges when:- Someone places a limit order to buy Yes at a price (e.g.,
$0.60) - Someone places a limit order to buy No at the complementary price (e.g.,
$0.40) - Since
$0.60+$0.40=$1.00, the orders match
$1.00 is converted into 1 Yes token and 1 No token, each going to their respective buyers.
Next Steps
Polymarket’s orderbook has no trading size limits — it matches willing
buyers and sellers of any amount. However, large orders may move the price
significantly. Always check orderbook depth before trading in size.