Kalshi Fair Odds Calculator
Turn a Kalshi YES bid and ask into fair probability, odds and a fee-adjusted break-even.
Optional: expected value of buying YES at the ask
Fair value is the midpoint of the book, an estimate of the true probability, not a guarantee. The taker fee is Kalshi's published formula, 0.07 × price × (1 − price) per contract, rounded up to the cent; fees can differ by series, so check the contract's fee schedule. Not financial advice.
Fair odds tell you what one market is worth. Arbitrage compares two.
Try the Polymarket vs Kalshi arbitrage calculator →How Kalshi prices become fair odds
A Kalshi YES contract pays $1 if the event happens, so its price in dollars is the market's implied probability. But there are two prices: the bid (what buyers offer) and the ask (what sellers want). The midpoint between them is the best simple estimate of the true probability, because it removes the half-spread each side pays to trade.
Fair decimal odds are 1 divided by that probability. American odds are the same number in the moneyline format used by sportsbooks, which makes Kalshi sports contracts easy to compare with a book.
Why the break-even is above the ask
Buying at the ask costs the ask plus the taker fee. You only profit if the true probability is higher than that total. The break-even figure shows the minimum probability you must believe before the trade has positive expected value.
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© 2026 Arbitrage Agent. Not financial advice. Trading involves risk of loss.