Prediction market odds converter (price, probability, American & decimal)
Type a price, a probability or sportsbook odds and see everything else, plus your payout.
How to use it: type any one number (a price in cents, a percentage, American odds like +150 or −200, or decimal odds like 2.50) and the rest update instantly. Then enter how much you'd spend to see how many contracts you get and what you'd win.
The formulas
| From | To | Formula |
|---|---|---|
| Price p (in dollars) | Implied probability | p × 100% |
| Price p | Decimal odds | 1 ÷ p |
| Price under 50¢ | American odds | +(1 − p) ÷ p × 100 |
| Price over 50¢ | American odds | −p ÷ (1 − p) × 100 |
| Kalshi fee | Fee in dollars | 0.07 × contracts × p × (1 − p), rounded up to the cent |
Worked example
A Yes price of 40¢ means a 40% implied chance, decimal odds of 2.50 and American odds of +150. Spending $20 buys 50 contracts. If you're right you receive $50, a $30 profit before fees.
OG offer, checked 27 September 2026
Trade $25, get $25 in rewards
Promo code: WINPREDITCS
Paid partnership with OG. New users only. Terms and conditions apply. Trading derivatives involves risk and may not be appropriate for all. Availability subject to jurisdictional limitations. For more information, visit OG.com. Terms apply.
Why convert at all?
- Compare with sportsbooks. If a sportsbook offers +130 and a prediction market prices the same outcome at 40¢ (+150), the market pays more.
- Compare platforms. The same event can trade a few cents apart on Kalshi and Polymarket.
- Check your edge. Only buy when you believe the true chance is higher than the implied probability, after fees. More in how to read prediction market odds.
Novig offer, checked 27 September 2026
Deposit $10, get $25 in trade credits
Promo code: WINPREDICTS
New users only. Restrictions & requirements apply. Not available in all states. 21+. Event contract trading involves risk & is not appropriate for all. Consider if it's appropriate for you in light of financial circumstances. See novig.com/terms for information. Terms apply.
Frequently asked questions
How do I convert a Kalshi price to odds?
Divide 1 by the price in dollars for decimal odds (40¢ → 2.50). For American odds under 50¢, use (1 − p) ÷ p × 100 (40¢ → +150).
What does 65¢ mean in odds?
About a 65% implied chance, decimal odds of 1.54 and American odds of about −186.
Does the converter include fees?
Tick "Include Kalshi-style trading fee" to apply Kalshi's published formula for most markets. Other platforms charge differently.
