Odds Converter: American, Decimal and Cents
Convert between prediction market cents, implied probability, American odds and decimal odds.
What one contract costs on Kalshi, Polymarket or Novig.
How it works
Prediction markets quote in cents, sportsbooks quote in American odds, and most of the rest of the world quotes decimals. They are the same information in three costumes, and the ability to move between them is what lets you compare a Kalshi contract against a sportsbook line.
The cent price is the most direct of the three: it is the implied probability. A contract at 52¢ means the market gives the outcome a 52% chance, and settles at $1 if it happens. American odds hide that behind a convention where favourites show the stake needed to win 100, and underdogs show the win on a 100 stake.
One warning about comparing across formats: a sportsbook line already has vig baked into it, so converting −110 to 52.4% gives you the book's marked-up number, not its actual opinion. Strip that out first with the vig calculator.
Frequently asked questions
How do you convert American odds to probability?
Positive odds: 100 ÷ (odds + 100), so +150 is 40%. Negative odds: |odds| ÷ (|odds| + 100), so −200 is 66.7%.
What does a contract price in cents mean?
The price is the probability. 52¢ means a 52% chance, and the contract pays $1 if the event happens — see how prediction markets work.
Are prediction market odds better than sportsbook odds?
Usually, because the margin is smaller — 4–5% on a sportsbook line against under 1% on a liquid prediction market. Compare the no-vig numbers, not the quoted ones.
Other calculators
For live prices instead of hypotheticals, see the Polymarket vs Kalshi arbitrage scanner, or compare the venues in our head-to-head breakdown.
