How to use the edge calculator
- Market price — what a "Yes" contract costs, in cents.
- Your estimate — your own probability that the event happens.
The calculator shows your edge in percentage points and your expected return per $1 staked.
The maths
- Edge = your probability − market price
- Expected return per $1 = your probability ÷ price − 1
Example: the market says 62¢; you think 70%. Edge = +8 points. Expected return = 0.70 ÷ 0.62 − 1 ≈ +$0.13 per $1. After a Kalshi taker fee of about 1.65¢ per contract (100 contracts), it’s closer to +$0.10. The two numbers measure different things: points of probability versus expected return on the money you put in.
If your estimate is below the price, the calculator suggests looking at "No" instead.
Edge at a glance
| Market price | Your estimate | Edge (points) | Expected return per $1 (before fees) |
|---|---|---|---|
| 30¢ | 35% | +5 | +16.7% |
| 50¢ | 55% | +5 | +10.0% |
| 62¢ | 70% | +8 | +12.9% |
| 80¢ | 85% | +5 | +6.25% |
| 90¢ | 92% | +2 | +2.2% |
The same 5-point edge is worth much more on a cheap contract than on a favourite — but cheap contracts also lose far more often, and longshots tend to be overpriced on most markets. A 2-point edge on a 90¢ favourite is usually wiped out by the fee and spread.
How much to stake
An edge tells you whether a trade is worth making, not how much to put on it. The Kelly criterion sizes a stake from your edge and the price; most traders use a fraction of it. Try the Kelly calculator — enter the contract's decimal odds (1 ÷ price) and your probability.
Use it honestly
- Be calibrated. Track your estimates; if your 70% calls win 55% of the time, adjust.
- Subtract costs. Fees and the spread eat small edges. See prediction market fees.
- Beware longshots. Cheap contracts are often overpriced — read implied probability.
- Size sensibly. Even good edges lose often. Never stake money you can't afford to lose.
Related: contract calculator · arbitrage calculator · wisdom of crowds.
