Calculators.
Fees, profit, odds, Kelly, and expected value. Nothing leaves your browser.
Takers pay 0.07 × contracts × price × (1 − price), capped at $1.75 per 100 contracts. Makers pay about a quarter of that. The calculators below run in your browser. Nothing is posted to a server, and nothing here places an order on Kalshi.
Use the fee calculator before you size a clip, and the profit calculator to see what a YES or NO fill is worth after the taker charge. The odds converter is for people who still think in decimal or American prices. Kelly and expected value are for when you think you have an edge; we show half-Kelly as the stake.
These tools do not pull the live book. If the ticket on kalshi.com disagrees with a number here, trust the ticket. Refresh the page and your inputs reset. That is the point: the math is local, and none of this is financial advice.
Start with fees if you are new. Move to profit once you can read a 60¢ contract. Use Kelly only after you can state a probability that is not just the last print. Expected value is the same idea in cents per contract.
If you are still learning what a YES contract is, read What prediction markets are first. If you already trade and only need the formula, stay here, then confirm the live ticket on the exchange.
The fee formula
Taker: 0.07 × C × P × (1 − P), capped at $1.75 per 100 contracts. Maker is about a quarter of that, capped at $0.44 per 100. P is the price in dollars (50¢ = 0.50). Worked example: 100 contracts at 50¢ → 0.07 × 100 × 0.50 × 0.50 = $1.75, which is the cap. The same 100 at 90¢ → 0.07 × 100 × 0.90 × 0.10 = $0.63. The full table lives on the fee guide. The live ticket on kalshi.com beats this page.
What each calculator is for
Fees size a clip before you send it. Profit is what a YES or NO keeps if the contract settles your way — it ignores book spread. The converter turns a Kalshi price into implied, decimal, and American. Kelly and EV are only useful when your probability is not the last print; we show half-Kelly. None of this places an order.
A market order pays the taker schedule. A limit that rests pays closer to the maker cap — see the trade guide. The 4.4 score and the six buckets sit on the review.