Free tools
Prediction market calculators
Six calculators for pricing a prediction market question. No account, no limits, and every result is a link you can share — the inputs live in the URL.
- Odds converterOne number in four notations — plus the contract price a prediction market would show for it.
- Payout calculatorWhat the position costs, what it returns, and the probability you need for it to be worth taking.
- Kelly criterion calculatorThe stake that maximises long-run growth — and the reason almost nobody should use all of it.
- Arbitrage calculatorTwo venues, two legs — and the fee line that decides whether the gap is real.
- Brier score calculatorA score on its own means nothing — this one comes with the number it has to beat.
- Crypto base rate calculatorTurn a price target into a frequency: how often this coin has covered that distance before.
These calculators do arithmetic on numbers you supply. They are not advice, and nothing here is a recommendation to take a position.