The Coin Flip Is The Most Expensive Trade On Kalshi

Most people searching for Kalshi fees expect a single number — a flat commission off the top. That number doesn't exist. Kalshi's trading fee is a curve: an identical 100-contract order can cost you $1.75 in fees or 7 cents, depending on nothing more than whether the market thinks the outcome is a coin flip or a near certainty.

Learn the shape of that curve and you can answer the question that actually matters: is the exchange cheaper than the sportsbook, or not? Nothing here is a promise of profit, and availability varies by state — see are prediction markets legal.

How Kalshi's Trading Fee Actually Works

Every Kalshi contract settles at either $1.00 or $0.00. It trades somewhere between 1 cent and 99 cents in between, and that price reads directly as a probability. A contract at 30 cents means the market thinks the event is roughly 30% likely.

Kalshi charges its trading fee as a percentage of the expected earnings on the contract rather than as a percentage of your stake. That sounds like accounting trivia. It is actually the whole design, and it explains the curve. Per Kalshi's published fee schedule — confirmed live against Kalshi's current fee page — a standard trade costs:

fee = round up(0.07 × C × P × (1 - P))

Where C is the number of contracts and P is the price in dollars, so 50 cents is 0.50. The round up is to the next cent. Some products sit outside this schedule entirely and are priced on their own, lower table, so check the current schedule rather than trusting the general formula if you're trading anything other than a standard sports contract.

The engine of that formula is the P × (1 - P) term, which is uncertainty itself. It is largest when P is 0.50, where it equals 0.25, and it shrinks toward zero as the price approaches either 1 cent or 99 cents — which is why a coin-flip contract costs the most and a near-certainty costs almost nothing.

So the maximum possible fee on 100 contracts is 0.07 × 100 × 0.25, which is $1.75. Hold onto that number. It is the single most useful figure on the exchange, and it is what we compare to a sportsbook next.

The formula above applies only to orders that fill immediately against something already on the book — you are the taker, and you pay for removing liquidity. Rest an order instead, at a price nobody is hitting yet, and you become the maker. Kalshi does not charge its standard trading fee on orders that sit unmatched, and on the markets that do carry a maker fee, the published rate runs at one quarter of the taker formula. Which markets carry a maker fee changes, so check Kalshi's fee schedule page rather than assuming. Patience is the discount, when the market you're trading has one. There is also no settlement fee and no membership fee — you are not charged to hold a contract to expiry or to collect on a winner.

Building a Kalshi combo?

run the combo through 10,000 sims before you buy it: 10,000 simulated games price every combo next to the price on Kalshi.

Kalshi Fees Vs. Sportsbook Vig

This is the comparison our readers actually want, and almost nobody runs it honestly. A sportsbook does not charge a visible fee. It charges you inside the price, which is exactly why it feels cheaper and often is not.

The sportsbook side. Take a standard game priced at -110 on both sides. That -110 implies a 52.38% break-even. Both sides together add to 104.76%, and that extra 4.76 points is the book's margin. Strip it out, which is what de-vigging means, and the fair price on each side is 50%. So the book is asking you to win 52.38% of the time on a proposition that is truly 50/50. Your cost is those 2.38 percentage points.

The Kalshi side. The same game, with the YES contract trading at 50 cents. Buy 100 contracts and you pay $50.00, plus the maximum fee of $1.75 that we met earlier. Total outlay: $51.75, against a $100 payout if you are right. Your break-even is 51.75 / 100, or 51.75%.

On a coin flip, the exchange's worst-case fee still requires a lower break-even than a standard -110 sportsbook price, by about 0.63 percentage points. That's the honest headline, and here are the honest counterweights, because the table above flatters Kalshi in two ways. First, it compares Kalshi against the sportsbook's standard price, and -110 is not the only price on the board — line shopping for the best number is still the highest-value habit in betting. Work backwards from Kalshi's 51.75% break-even and the crossover American price sits at about -107.25: a book at -107 or better beats the exchange outright, and the reduced-juice books that post -105 beat it comfortably at 51.22%. Second, the Kalshi fee is charged per trade, so exiting before settlement means paying again on the way out — two coin-flip trades cost 3.5 points against a fair price, worse than the -110 you were trying to beat. The edge belongs to holding to settlement and shopping the sportsbook price, resting orders when the market lets you, not to trading in and out, and none of it means anything if the order book is too thin to fill your size at the price you want.

In Summary

A live comparison, stamped Friday, September 11, 2026, 11:39 AM ET: 100 contracts at 50¢ costs $50, plus the maximum $1.75 fee, for $51.75 against a $100 payout. 100 contracts at 10¢ costs $10, plus a 63-cent fee, for $10.63 against a $100 payout. A sportsbook offering that same 50¢ (pick'em) side at a standard -110 needs a 52.38% break-even to make money, worse than Kalshi's worst-case coin-flip fee of 51.75%.

• The ceiling is $1.75 per 100 contracts at a 50-cent price; the fee decays toward both ends of the board, and resting orders pay less than that.
• There is no settlement fee, and deposits and withdrawals by bank transfer are free.
• Whether Kalshi beats a sportsbook depends on the price you're comparing it to — it beats a standard -110, but a book at -107 or better wins, so where you shop matters more than which venue you pick.

More on this: Kalshi Fees Vs. Sportsbook Vig: Which Costs You More? · Kalshi Profit And Loss Tracking: Your Real P&L, Fees Included · Polymarket Fees: What It Actually Costs To Trade