Calculator guide
Implied Probability Formula for Event Contracts
Convert YES and NO prices into readable percentages, compare break-even probabilities, and understand what a contract price really means.
Educational note: This guide explains probability and market structure. It is not a recommendation to trade, and availability depends on local rules.
Basic formula
For a simple $1 payout event contract, a YES price of 37 cents corresponds to roughly 37% implied probability before fees, spreads and slippage.
YES and NO relationship
In a frictionless two-outcome market, YES plus NO should be close to $1. In real markets, spreads and fees can create gaps. Check the live order book and rules before acting.
Break-even thinking
If you pay 42 cents for YES, the outcome must be true more than about 42% of the time over repeated comparable situations to break even before costs. The calculator helps translate that intuition.
Next step: compare a market price with your own estimate, then read the rules before opening any external market.
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