Enter a yes/no contract price, your probability estimate, budget, and fee rate to model expected value and risk.
A YES contract priced at 42 cents costs about $0.4284 after fees and settles at $1 if that side resolves as true. The break-even probability is 42.84%.
This is an educational event-contract simulation. It does not connect to Kalshi, Polymarket, ADI PredictStreet, or any trading venue, and it does not place trades.
Method
A binary event contract settles at a fixed value when the selected outcome occurs and at zero when it does not. The calculator compares contract cost, fees, settlement value, budget, and your probability estimate to show break-even probability, maximum profit, maximum loss, and expected value.
Educational example
A contract costing $0.42 with $0.01 total fees and a $1 settlement value has a $0.43 effective cost.
The approximate break-even probability is 43%. A 50% probability estimate implies positive modeled EV, but liquidity and jurisdiction rules still matter.
Translate contract cost and fees into a required probability.
Normalize costs before comparing prices, subject to each venue's rules.
Keep the downside visible before focusing on possible profit.
Venue fees, bid-ask spread, liquidity, partial fills, settlement criteria, taxes, and legal availability can all change the result. This site does not connect to or execute trades on prediction markets.
It is a rough market-implied probability before fees, spread, and other frictions.
For a long binary contract, maximum loss is generally the contract cost plus applicable fees.
No. It is an independent educational calculator with manual inputs.