Odds & expected value calculator
Short answer
A contract price in cents is the market's probability. 62¢ = 62%. Your expected value is the gap between that number and your own estimate, multiplied by how many contracts you hold.
Implied probability
62.0%
Decimal odds
1.61
Contracts
322.6
Payout if right
$322.58
Profit if right
$122.58
Expected value
$25.81
Prices move fast on short-dated markets — check the live book before committing.
Reading the numbers
- Implied probability is what you are being charged for the outcome. It already includes the crowd's information.
- Decimal odds translate the same price into sportsbook terms, useful if you are arbitraging against a bookmaker line.
- Expected value is the only number that decides whether the trade is worth taking. Everything else is presentation.
Watch the spread
On thin markets the bid and ask can be several cents apart. Price your EV off the side you would actually get filled on, not the mid — a 2¢ spread wipes out most small edges, especially on five-minute contracts where you round-trip frequently.
FAQ
+ How do I convert prediction market cents to probability?
Divide the price by 100. A contract at 62¢ implies a 62% probability, because it pays $1 if the event happens and the market is willing to pay 62 cents for that claim.
+ How is expected value calculated on a binary contract?
EV per contract = your probability × (1 − price) − (1 − your probability) × price. Positive EV means the contract is underpriced relative to your estimate.
+ What are decimal odds for a prediction market contract?
Decimal odds equal 1 ÷ price in dollars. A 25¢ contract is 4.00 in decimal odds — a $1 payout for every 25 cents risked.