Kalshi fees explained, from the taker formula to breakeven
Kalshi charges takers 0.07 × contracts × price × (1 − price), rounded up per order. Why the fee peaks at 50%, a worked table, and how limit orders avoid it.
Kalshi's fee on a filled order is 0.07 × C × P × (1 − P), rounded up to the next cent, where C is the number of contracts and P is the price as a decimal. For 10 contracts at 50% that is 18 cents; for 10 contracts at 95% it is 4 cents. The fee is charged when a taker order fills, not when a contract settles, and orders that rest on the book as makers pay a lower rate, often nothing.
The formula
Three things about the shape of the formula matter more than the 0.07.
The P × (1 − P) term is the variance of a yes-or-no outcome. It is 0.25 at 50% and falls symmetrically toward zero at both ends: 0.0475 at 5% and at 95%, 0.0099 at 1% and at 99%. Kalshi is charging in proportion to how uncertain the contract is, so a coin-flip contract pays the most per contract and a near-certainty pays almost nothing. One side effect is that buying the 97% side of a question that is already decided costs less in fees than the size of the order would suggest.
The fee is per order, rounded up. One contract at 50% has a formula fee of 1.75 cents and a charged fee of 2 cents. A hundred contracts at 50% has a formula fee of $1.75 and a charged fee of $1.75. Splitting one order into many small ones pays the rounding many times.
The rate is 0.07 on the general schedule as of September 2026, and a few series carry their own rate on the fee page. Check the venue's own page before relying on it.
Taker, maker, and what a limit order is
A taker order crosses the spread and fills against an order already resting on the book. A market order is always a taker. A limit order that is immediately matchable, a bid at or above the best ask, is also a taker; the word "limit" does not make an order a maker. A maker order rests on the book at a price no one is currently willing to hit, and earns its status by waiting. When a taker arrives and fills it, the maker pays the maker rate, which on most Kalshi markets is zero and on some is a reduced multiple of the same formula. How Kalshi works covers the order book itself.
Nothing is charged at settlement. A position held to expiry pays one fee, on the way in. A position sold before expiry pays two, one on each fill, each computed at the price of that fill.
Why 50% is the worst place to pay
At P = 0.5 the formula is at its maximum, 1.75 cents per contract. That is 3.5% of the 50-cent stake and, more usefully, 1.75 points of price: a contract bought at 50 with the fee is a contract bought at 51.75. At P = 0.05 the fee is 0.3325 cents per contract, which is 6.65% of the 5-cent stake but only 0.33 points of price. In stake terms the cheap contract costs more in fees; in probability terms it costs less. The second framing is the one that matters, because price is probability and the fee is a shift in the probability you need to be right.
A worked example
Ten YES contracts at five prices, taker fee on entry only, held to settlement. Payout if YES is $10.00.
| Price | Formula | Fee charged | Stake | Total cost | Profit if YES | Breakeven |
|---|---|---|---|---|---|---|
| 5% | $0.03325 | $0.04 | $0.50 | $0.54 | $9.46 | 5.4% |
| 25% | $0.13125 | $0.14 | $2.50 | $2.64 | $7.36 | 26.4% |
| 50% | $0.17500 | $0.18 | $5.00 | $5.18 | $4.82 | 51.8% |
| 75% | $0.13125 | $0.14 | $7.50 | $7.64 | $2.36 | 76.4% |
| 95% | $0.03325 | $0.04 | $9.50 | $9.54 | $0.46 | 95.4% |
Breakeven is total cost divided by payout: the probability at which the trade returns exactly what it cost. The fee moves it by 0.4 points at the ends and 1.8 points in the middle. A trader who thinks a Fed cut is a 52% proposition and sees YES offered at 50 has a 2-point edge before fees and a 0.2-point edge after, on a taker order. Posting a bid at 50 instead and waiting for it to fill as a maker keeps the full 2 points, if it fills, and the "if" is the price of the discount.
Add an exit. Buy 10 at 50%, sell 10 at 60% before settlement: entry fee $0.18, exit fee 0.07 × 10 × 0.60 × 0.40 = $0.168, charged as $0.17, gross gain $1.00, net $0.65. The round trip ate 35% of a 10-point move. On a CPI contract that moves 10 points in a morning, the schedule is the difference between a trade and a wash, which is why the payout-versus-profit arithmetic starts with the fee and why how Fed and CPI markets work spends so long on the release minute.
How this compares with the other venue
Polymarket's global order book has historically charged no trading fee on most markets, with gas for trades covered by the venue, and the Polymarket US app has its own schedule. That does not make Polymarket cheaper by default: a spread is a cost too, and a 4-point spread on a thin market costs more than Kalshi's 1.75-point maximum. Polymarket versus Kalshi does the full comparison; the short version is that on Kalshi the cost is printed on the order ticket and on Polymarket it is hidden in the book.
What to check before you trade
- The fee page for the series you are trading; the general 0.07 rate is not universal.
- Whether your limit order is matchable now, in which case it is a taker.
- The breakeven after fees, which is the price plus the fee in points, not the price.
- Whether you plan to exit before settlement, since that doubles the fee.
- How many orders you are splitting into, because rounding is per order.
- The tax treatment of fees, which reduce the net profit the venue reports.
Nothing on this page is investment advice, and the venue's current rule text and fee page are the only things that pay.
Reviewed Thu, Sep 17, 2026. Guides are re-read against the live markets every week; fees, rules, and availability change, and the venue’s own page is the final word.