Prediction Market Calculator: Payout, Profit, EV, and Arbitrage
Convert prediction market prices into probabilities and odds, calculate potential payouts and expected value, model a binary arbitrage, and size a full hedge.
Payout, profit, and odds
Estimate contracts and settlement value from a market price. Fee and slippage assumptions are editable.
Winning contracts are modeled as paying $1. Actual fees, fills, settlement rules, and taxes can differ.
Expected value
Compare your probability estimate with the effective price after your execution assumptions.
Binary arbitrage calculator
Size opposing contracts so both outcomes produce the same gross payout.
This calculation excludes fees, slippage, transfer costs, unmatched legs, and resolution-rule differences.
Full payout hedge
Estimate the opposing contracts needed to equalize gross settlement payout.
This equalizes contract count, not net profit. Include your original entry cost and all execution fees when evaluating the hedge.
Frequently asked questions
Direct answers about this prediction market tool and its limitations.
How do I calculate a prediction market payout?
Divide the stake by the contract price in dollars to estimate the number of contracts. If the outcome resolves in your favor, each winning contract is generally modeled as paying one dollar before fees, slippage, taxes, and venue-specific rules.
What does a 45-cent prediction market price mean?
A 45-cent price represents an implied probability of approximately 45%, decimal odds of about 2.22, and positive American odds of about +122.
How is expected value calculated?
Expected value multiplies your estimated probability by the possible payout, then subtracts the total cost. The result depends on the quality of your probability estimate and execution assumptions.
Does the arbitrage calculator guarantee a profit?
No. It only models prices mathematically. Fees, slippage, unmatched orders, access restrictions, settlement differences, and changing quotes can remove the apparent edge.