04Probability edge

Prediction Market EV Calculator

Compare your probability estimate with the market price to measure edge, expected value, and Kelly size.

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Transparent mathFormula and assumptions included

Market price

Your estimated probability

Amount invested

Expected profit$30.95

Expected value30.95%

Probability edge+13.0 pts

-100%31.0%150%

Market probability42.0%

Your probability55.0%

Full Kelly fraction22.4%

iMethodology

How this result is calculated

Based on your inputs

Every result is calculated from the values shown on this page. No hidden market forecast or AI estimate is added.

Updates instantly

Change any input and the result updates immediately. Your inputs remain in your browser.

Assumptions are visible

Fees, return, yield, risk, and probability assumptions are shown as inputs instead of hidden in the result.

This calculator is for education and scenario analysis only. It does not account for taxes, slippage, liquidity, or every platform-specific fee.