Learn How to Trade Prediction Markets
Four levels. Start at the beginning or jump to what you need. Every lesson has a companion tool you can use immediately.
What prediction markets are and how to read them. Start here if you've never placed a trade.
How to Read Prediction Market Prices
What the cents mean, how to convert them to probabilities, and what the vig actually costs you.
Reading Kalshi Like a Bond Desk
The mental model that reframes prediction markets as mispriced probability instruments. The foundation for everything else.
The four math frameworks every serious prediction market trader uses. Learn these before placing real money.
Expected Value Is the Only Number That Matters
How to calculate edge from a market price and your probability estimate. The foundation of every trade decision.
Kelly Criterion: Stop Overbetting Your Edge
The optimal position sizing formula. Why fractional Kelly is the professional standard and how to apply it.
Bayesian Reasoning: How Sharp Traders Update Beliefs
How to revise your probability as new evidence arrives — without overreacting to noise.
Base Rates: The Starting Point Everyone Ignores
Historical frequency data as an anchor. Where prediction markets diverge from history most often.
Specific strategies for finding and trading edge — combos, arbitrage, and cross-platform gaps.
How Kalshi Combos Work
Multi-leg combo mechanics, combined probability math, and the situations where combos offer real edge.
Cross-Platform Arbitrage: Find and Trade Price Gaps
When Kalshi and Polymarket price the same event differently, one is wrong. How to identify and size the trade.
How the quant tools on this site work under the hood. Read these after you've traded for a while.
The Options Trader Who Cracked Polymarket
Binary options time-value pricing applied to prediction markets. The model, the math, and why the crowd ignores theta.
How the Polymarket Mispricing Scanner Works
A two-agent Bayesian swarm that scans Polymarket every morning. How it finds 5pp+ mispricings and sizes them.
Bayesian Mispricing: The Spec in Plain English
The same engine explained without the math — what the two agents do, why it works, how to read the output.
Prediction Markets — Common Questions
What are prediction markets?↓
Prediction markets are exchanges where you buy and sell contracts that resolve to $1 if an event happens and $0 if it does not. The price — quoted in cents — represents the crowd's implied probability. A contract at 65¢ means the market thinks there is a 65% chance the event resolves YES. Platforms include Kalshi, Polymarket, DraftKings Predictions, and FanDuel Predicts.
How do you make money on prediction markets?↓
You make money by finding contracts where the market price is wrong relative to the true probability — positive expected value (EV). If the market prices an event at 40¢ but you estimate the true probability is 55%, that is a +16.8% edge. Over enough trades, positive EV compounds into profit. The tools on this site — EV calculator, Kelly sizing, arb scanner, and more — are built to find and size these edges.
What is the Kelly Criterion in prediction markets?↓
The Kelly Criterion is the mathematically optimal formula for sizing a bet given your edge and the payout. In prediction markets: f* = (p×b − q) / b, where p is your win probability, q = 1−p, and b is the net payout odds. Professional traders typically use half or quarter Kelly to reduce variance. Never bet full Kelly without very high confidence in your probability estimate.
What is the difference between Kalshi and Polymarket?↓
Kalshi is a CFTC-regulated US exchange — legal in most states, real cash, federally licensed. Polymarket is a crypto-based decentralized prediction market — broader market selection, larger volumes on political and macro events, but requires a crypto wallet and is not regulated in the US. Both price the same events, which creates arbitrage opportunities when their prices diverge.
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