Prediction market odds, compared and explained

A prediction market lets you trade on the outcome of a real event: an election, a Federal Reserve decision, a championship. Each contract pays $1 if the event happens and nothing if it does not, so its price in cents reads as a probability. A contract at 62¢ says the market gives the outcome a 62% chance.

Because traders put money behind their views, prices move as soon as information arrives, and across large samples they have been well calibrated. The two largest venues are Polymarket, which settles in USDC, and Kalshi, a CFTC-regulated exchange that settles in dollars. Start with how prediction markets work, or read the evidence on how accurate they are.

Every ten minutes we pull prices for the same markets from Polymarket and Kalshi, match the outcomes by name and show where the two venues disagree. When a gap is wide enough to lock in a profit after both venues' fees, the arbitrage scanner flags it with the return, the annualised yield and the prices to trade.

Around that data sit reviews of every platform worth trading on, guides to fees, taxes and regulation, and odds coverage for the markets people follow most. Meet the editors who write them on our authors page. Some links are affiliate links, and we label them.