What is a prediction market? A beginner’s guide

Last updated July 8, 2026

A prediction market is a place where people forecast whether a future event will happen by trading on outcomes like “Yes” or “No”, and the live price of each outcome reflects the crowd’s best estimate of the odds. If a market reads “Will Spain win the 2026 World Cup? Yes 17%”, it means traders, taken together, currently think there is roughly a 17% chance it happens. The number is not set by an expert or a bookmaker — it is set by everyone trading, and it moves in real time like a live scoreboard for things that have not happened yet.

There are two flavours. Real-money prediction markets (such as Polymarket and Kalshi) use actual cash and let you withdraw winnings. Play-money prediction games (such as OmnidiaMarket and Manifold) use virtual tokens with no monetary value — so it is a game, not a financial product. Same core mechanic, completely different stakes. Virtual tokens only. No real money. No cash-out. Just bragging rights. 18+.

How do prediction markets work?

Prediction markets work by turning a question about the future into tradeable outcomes that each pay a fixed amount if they come true. Take a simple Yes/No market: “Will it rain in London on Saturday?” Each “Yes” share is designed to be worth 1 token if it rains and 0 if it does not. You back the outcome you believe in; if you are right when the market resolves, your winning shares are worth their full value, and if you are wrong they are worth nothing. The price you paid going in is the crowd’s live estimate of the odds at that moment.

The magic is in step 4: nobody dictates the odds. The price drifts to wherever the crowd’s collective conviction settles, which is usually a sharper forecast than any single loud opinion.

Why does the price equal the probability?

The price is the probability because of how the shares are built. Each “Yes” share is worth 1 token if the event happens and 0 if it does not, so a share trading at 0.63 tokens means the crowd believes there is about a 63% chance — people will pay up to 63% of the full value to hold it, no more and no less. If traders think “Yes” is too cheap they buy, which pushes the price up; if they think it is too expensive they sell, pushing it down. The price comes to rest exactly where the crowd’s collective confidence balances out. That is why a prediction is shown as a percentage: 0.63 tokens = 63% chance.

Two rules make any market instantly readable. First, all outcomes add up to 100% — “Yes 64% / No 36%” always sums to 100, and so does a four-way market. Second, a price near 50% means a genuine coin flip: the crowd is split and nobody really knows. You are never reading a promise; you are reading a consensus guess expressed as a number.

Real-money vs play-money prediction markets

This is the line that matters most, because it is the difference between a regulated financial product and a free social game. Real-money markets take deposits and pay real winnings, which means real losses are possible and they are regulated like financial or wagering products. Play-money markets use virtual tokens with no cash value that can never be redeemed — so you cannot lose a dollar, and the reward is status, not money. OmnidiaMarket is firmly in the play-money lane, by design: it is the fun, zero-risk version. Virtual tokens only. No real money. No cash-out. Just bragging rights. 18+.

Is a play-money prediction market gambling? No. Real-money gambling means real money in and real money out; a play-money game has neither, so there is nothing financial to win or lose. It is the same predict-the-outcome thrill as fantasy football or trivia night — the stakes are pride, not your paycheck.

Examples of prediction markets

Prediction markets can cover almost anything with a clear, knowable answer. The classic ones are about elections, sports and economics — “Who will win the election?”, “Will the home team keep a clean sheet?”, “Will inflation top 3% this year?” A single tournament like the World Cup spins off hundreds of markets, from “Will Brazil win it all?” to deep props — predictions on the details of a match, such as the number of cards, total corners, the exact final score, or the first goalscorer.

• Binary (Yes/No): “Will England reach the semi-final? Yes 38% / No 62%.”
• Multiple choice (2–10 outcomes): “Who wins the Golden Boot? Mbappé 22% / Haaland 19% / Kane 14% / …” (all options sum to 100%).
• Deep prop: “How many corners in the final? Over 9.5 / Under 9.5.”
• Personal / private: “Will Dave actually finish the marathon?” — a playful market inside a private group of friends, scored with tokens.

That last category is what makes OmnidiaMarket different: alongside the public, niche, deep-prop markets, you can spin up a market about your friends’ real lives in a private room and let the group chat argue it out with tokens. It is only tokens — the prize is calling it first.

Frequently asked questions

What is a prediction market in simple terms?

A prediction market is a live scoreboard for the future. People forecast whether an event will happen by trading on outcomes, and the price of each outcome is the crowd’s estimated chance it comes true. “Yes 70%” means the crowd thinks it is about 70% likely — exactly like a 70% chance of rain.

Are prediction markets the same as gambling?

Not necessarily. Real-money prediction markets share traits with wagering and are regulated accordingly. Play-money prediction games like OmnidiaMarket have no real money and nothing to redeem, so there is nothing financial to win or lose — it is a social game for bragging rights, the way fantasy football is.

What does the percentage on a prediction market mean?

It is the crowd’s estimated chance the outcome happens, just like a weather forecast. “Yes 64%” means roughly a 64% chance. The percentages of all outcomes always add up to 100%, and a price near 50% means the crowd is genuinely split.

Are prediction markets accurate?

Often surprisingly so. Because the price reflects the pooled judgment of many people who each have a stake in being right, prediction markets frequently forecast elections and sports outcomes as well as or better than polls and pundits. They are not crystal balls — a 70% market still misses three times in ten — but the crowd’s number is usually sharper than any single guess.

How do I start with a prediction market?

Pick a play-money app so there is zero financial risk while you learn. Read a market in four glances — the question, the big percentage (the odds), the volume (how busy it is), and the closing time — then back the outcome you believe in. On OmnidiaMarket you can even create your own market about your friends in under a minute. Virtual tokens only. No real money. No cash-out. Just bragging rights. 18+.

Keep reading

• Are prediction markets gambling?
• How to predict with friends
• How OmnidiaMarket works
• Prediction glossary
• OmnidiaMarket vs Kalshi

Virtual tokens only. No real money. No cash-out. Just bragging rights. 18+.