How Prediction Markets Work: Prices, Probability & Payouts

Prediction markets work by turning a future event into a tradable contract. The contract price becomes a live probability signal, and the final resolution determines whether the contract pays out.

This is the mechanics page. If you need the simple definition first, start with what prediction markets are.

The Basic YES/NO Contract

Most beginner-friendly prediction markets use YES/NO contracts. The market asks one clear question, and each side represents one possible answer.

• YES wins if the event happens under the market rules.
• NO wins if the event does not happen under the market rules.
• The winning side usually settles at $1.00.
• The losing side usually settles at $0.00.

The important detail is that you can often trade before the event resolves. You are not always locked into waiting for the final outcome.

What a $0.63 Price Means

If a YES contract trades at $0.63, the market is roughly pricing the event at a 63% probability. If it trades at $0.28, the market is roughly pricing the event at 28%. The probability pricing explained guide develops this relationship with bid, ask, fees, and break-even examples.

That number is not a promise. It is a traded estimate. Buyers and sellers are constantly pushing the price up or down based on data, news, positioning, and risk appetite.

How Payout Math Works

The simple payout formula is easy to remember: if you buy a contract at $0.40 and it settles at $1.00, the gross gain is $0.60 per contract before platform costs. If it settles at $0.00, the loss is the $0.40 paid.

A 100-contract position at $0.40 costs $40. If it wins and settles at $1.00, the position pays $100. If it loses, it pays $0. If the market moves to $0.70 before resolution, selling early would return $70 before any costs.

For quick sizing and payout checks, use the YES/NO contract calculator.

Why Prices Move

Prices move when traders revise their view and actually trade. News by itself does not move a market unless participants act on it.

A rate-cut market might trade at 35% before an inflation report. If the report is weaker than expected, traders may buy YES and push the price toward 55%. If a later official comment pushes against that interpretation, the same market can fall back again.

That is why price movement is useful: it shows how the market is processing information in real time. For a deeper reading framework, see how traders read probability movements.

Liquidity and Spread

Liquidity is how easy it is to trade without moving the price too much. A liquid market has enough buyers and sellers near the current price. A thin market may have wide gaps between bids and asks.

The spread is the difference between the best price someone is willing to pay and the best price someone is willing to sell for. A tight spread can make entry and exit cleaner. A wide spread can quietly make a trade worse before the event even moves. Use the liquidity and spread guide for order-book depth and executable-price examples.

Resolution Rules

Every prediction market needs rules that define what counts as YES and what counts as NO. Those rules matter. A headline may sound obvious, but the contract resolves according to the written criteria.

• Check the exact event deadline.
• Check the named data source or resolution source.
• Check whether edge cases are included or excluded.
• Check whether the wording matches the claim you think you are trading.

Step-by-Step Example

Here is a clean mechanics example using a rate-decision market. The question is whether the central bank cuts rates at the next meeting.

• The YES contract trades at $0.35.
• You buy 100 YES contracts, so the position costs $35.
• New economic data comes in weaker than expected, and YES rises to $0.55.
• You can sell at $0.55 for $55 before resolution, or keep holding and accept the final settlement risk.
• If YES eventually wins, the position settles at $100. If YES loses, it settles at $0.

The example is not a recommendation. It is a mechanics walkthrough: entry price, position cost, price movement, exit option, and resolution.

Where Beginners Misread the Mechanics

• They treat a 70% price as a guarantee instead of a probability.
• They ignore spread and liquidity.
• They do not read resolution rules before entering.
• They focus only on being right, not on whether the current price is reasonable.
• They size positions too large before understanding settlement risk.

What to Read Next

Once the mechanics are clear, use the prediction markets beginner guide for a learning path, platform-selection steps, and a first-trade checklist.