Prediction market odds converter
Type in any box to convert between a Kalshi or Polymarket price in cents, implied probability, American odds and decimal odds. Handy for comparing a prediction market with a sportsbook line.
¢
Kalshi / Polymarket price
%
Chance the market gives it
e.g. -150 or +200
Total return per $1
A 40¢ contract implies a 40% chance. $100 buys 250 contracts, which return $250.00 if it wins, a profit of $150.00 before fees.
Conversion formulas
With p the implied probability (cents ÷ 100):
decimal = 1 ÷ pAmerican = p > 0.5 ? −100 × p ÷ (1 − p) : +100 × (1 − p) ÷ pp = 100 ÷ (American + 100) for + odds, |American| ÷ (|American| + 100) for − oddsQuick reference
| Cents | Probability | American | Decimal |
|---|---|---|---|
| 10¢ | 10% | +900 | 10.00 |
| 25¢ | 25% | +300 | 4.00 |
| 40¢ | 40% | +150 | 2.50 |
| 50¢ | 50% | +100 | 2.00 |
| 60¢ | 60% | -150 | 1.67 |
| 75¢ | 75% | -300 | 1.33 |
| 90¢ | 90% | -900 | 1.11 |
Frequently asked questions
- How do prediction market prices relate to probability?
- A contract that pays $1 trading at 40¢ implies a 40% chance. The price in cents is the implied probability in percent.
- How do I convert cents to American odds?
- For prices under 50¢, American odds are +100 × (100 − cents) ÷ cents, so 40¢ is +150. For prices over 50¢ they are −100 × cents ÷ (100 − cents), so 60¢ is −150. 50¢ is +100 (even money).
- How do I convert cents to decimal odds?
- Divide 100 by the price in cents. A 40¢ contract is 2.50 in decimal odds: every $1 staked returns $2.50 including the stake.
- Do these conversions include fees?
- No. They convert the quoted price only. Use the fee calculator to add Kalshi or Polymarket fees to get your real cost.
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Calculations run in your browser and are estimates for education only, not financial advice. Venue fee schedules change; check the venue before you trade.