Prediction Market Fees, Explained
A prediction-market trade costs you a taker fee that scales with how uncertain the contract is, and on the two CFTC-regulated US venues it peaks at the coin-flip price. Buying 100 contracts at 50 cents costs $1.75 in fees on Kalshi and $1.50 on Polymarket US; the same 100 contracts at 10 cents cost $0.63 and $0.54. Deposits and standard withdrawals are free on the main rails at both, so the trading fee is the number that matters.
Both venues rewrote their fee schedules in July 2026, and both now use the same shape of formula rather than a flat percentage. This guide explains that shape, publishes what each side charges, and gives you a calculator to price your own trade. Every figure here comes from the venues’ published schedules as recorded in our facts ledgers, verified July 22, 2026.
Why the Fee Peaks at 50 Cents
Both venues charge a fee proportional to price times one minus price. That expression is largest when the price sits at 50 cents and shrinks toward zero at both extremes, so the fee tracks how genuinely uncertain the contract is. A true toss-up costs the most to trade; a contract the market has nearly settled at 2 cents or 98 cents costs almost nothing.
The formulas, in plain terms
Kalshi charges 0.07 times contracts times price times (1 minus price), rounded up to the next cent, per its published fee schedule. Polymarket US charges 0.06 on the same shape with banker’s rounding and pays makers a rebate of 0.0125 on that shape, per its fee documentation. Same curve, different heights.
The practical reading: churning coin-flip markets is the most expensive way to trade, and taking a position on something the market considers close to decided is nearly free. That is a deliberate design choice rather than an accident, and it is the opposite of a sportsbook, where the margin is widest on the markets the book considers hardest to price.
What 100 Contracts Cost at Every Price
Computed from the two published formulas at build time, per 100 contracts:
| Contract price | Kalshi taker fee | Polymarket US taker fee | Polymarket maker rebate |
|---|---|---|---|
| 5¢ | $0.34 | $0.28 | $0.06 |
| 10¢ | $0.63 | $0.54 | $0.11 |
| 25¢ | $1.32 | $1.12 | $0.23 |
| 50¢ | $1.75 | $1.50 | $0.31 |
| 75¢ | $1.32 | $1.12 | $0.23 |
| 90¢ | $0.63 | $0.54 | $0.11 |
| 99¢ | $0.07 | $0.06 | $0.01 |
Per 100 contracts on standard markets. Kalshi rounds each fee up to the next cent; Polymarket US uses banker’s rounding, so small trades can round to $0.00. Kalshi’s schedule carries per-series variations, including some fee-free series. Figures from both venues’ published fee schedules, verified July 22, 2026.
Read down the two fee columns and the pattern is consistent: Polymarket US charges less per trade at every price on standard markets, and the gap is widest exactly where the volume is, on the near-even contracts. That is a statement about fees on these examples, not about which venue is the better place to trade. Our head-to-head comparison weighs fees against market depth, funding rails, and the rest.
Worked Examples
Two concrete trades, computed the same way the calculator below computes yours:
| The trade | Kalshi taker fee | Polymarket US taker fee | If you were the maker |
|---|---|---|---|
| 100 contracts at 50¢ ($50 at risk) | $1.75 | $1.50 | +$0.31 to the maker |
| 100 contracts at 10¢ ($10 at risk) | $0.63 | $0.54 | +$0.11 to the maker |
Taker side unless noted. The maker column shows what a resting limit order earns on Polymarket US, where makers are paid rather than charged; Kalshi charges no maker fee on most markets.
Maker and Taker Are the Fee Question That Matters
Every order is one or the other. You are a taker when you accept a price already sitting on the order book, which is what happens by default when you hit buy. You are a maker when you post a price and wait for someone to trade against it.
- Kalshi: 0 on most markets; designated series carry maker fees of roughly $0.02-$0.44 per 100 contracts (e.g. certain tennis, soccer, crypto-adjacent series). Charged only when a resting order executes; canceling is free.
- Polymarket US: makers are paid a rebate at the point of trade, up to $0.31 per 100 contracts at coin-flip prices, rather than charged a fee.
- Neither venue charges a settlement or membership fee. None. No membership fee.
If you are patient enough to name your price instead of crossing the spread, the fee difference between the two behaviors is larger than the difference between the two venues. That is the single most useful thing on this page.
Volume Rebates
Polymarket US layers a volume program on top of the formula, rebating part of your taker fees based on the prior calendar month’s traded volume: 10 percent back at $250,000, 25 percent at $1 million, and 50 percent at $10 million, paid weekly. Kalshi’s published schedule instead varies by series, with 142 series carrying non-standard terms and a handful charging no fee at all as of the last verification.
For an ordinary recreational trader, neither program changes the arithmetic much. Both matter a great deal if you are trading six figures a month, which is worth knowing before you assume the headline rate is what you will pay.
What Deposits and Withdrawals Cost
| Method | Kalshi | Polymarket US |
|---|---|---|
| Bank transfer (ACH) | Free | No platform fee |
| Debit card | 2% processing fee (also applies via Apple Pay / Google Pay) | No platform fee |
| PayPal / Venmo | Free | Not offered |
| Wire | no Kalshi fee ($1,000 minimum) | No platform fee |
| Withdrawals | No Kalshi fee on ACH; debit withdrawals normally instant (processor security checks can add delay). | No platform-charged withdrawal fee |
Platform-charged fees only; your own bank or card issuer may add its own. Verified July 22, 2026.
The one line to notice is the debit-card surcharge on Kalshi, which also applies through Apple Pay and Google Pay. Funding by bank transfer avoids it entirely, and on a $500 deposit that 2 percent is larger than the fees on many individual trades.
Price Your Own Trade
Enter a contract price and a quantity and the calculator applies both venues’ published formulas, showing the taker fee on each side plus what the position pays if it settles yes. It runs entirely in your browser on the same verified fee data as the tables above.
Set a contract price and size to compare each venue's taker fee and outcome math side by side, computed from the published fee schedules.
Fees per each venue's published schedule (Kalshi update effective 7/7/2026; Polymarket US effective 7/1/2026), verified August 17, 2026. Taker (market-order) fees shown; maker treatment differs. Polymarket US also lists volume-based taker fee rebates starting at $250K in monthly volume. Not financial advice. 21+.
What About the Newer Venues?
The 2026 wave of entrants (DraftKings Predictions, FanDuel Predicts, ProphetX, Novig, and the event-contract surfaces inside Crypto.com and Robinhood) each publish their own fee terms, and those terms are moving as the products mature. We do not print their numbers here because this page’s standard is a sourced ledger entry re-verified on a schedule, and only the two incumbents have one today.
If you are comparing a newer venue, read its published fee page directly and check two things beyond the headline rate: whether makers and takers are charged differently, and whether the fee scales with price the way the formulas above do or sits flat. Those two answers determine what you actually pay far more than the advertised percentage does. Our plain-English explainer covers the maker and taker distinction if it is new to you.
The Cost That Is Not a Fee
Fees are the visible cost. The spread is the one that quietly does more damage to active traders. Every market shows a highest bid and a lowest ask, and the gap between them is what you give up by trading immediately instead of waiting.
On a busy contract that gap might be a single cent, which is trivial next to the fee. On a thin market it can be five or ten cents, which dwarfs any fee on this page: buying at the ask and selling at the bid on a ten-cent spread costs you ten percent of a 50-cent contract before the event even resolves.
The practical rule
Compare venues on fees, but compare individual markets on liquidity. A cheaper fee schedule on a market nobody trades is more expensive in practice than a slightly higher fee on a deep one.
How This Compares With Sportsbook Vig
A sportsbook builds its margin into the odds, so a standard -110 line on both sides means the two prices add up to more than a fair market would. An exchange does the opposite: prices are set by traders and sum to roughly a dollar, and the venue’s cut arrives as a separate, visible line item.
Which structure leaves you with more depends on how you trade rather than on arithmetic alone. Frequent in-and-out trading pays the explicit fee repeatedly; holding a position to settlement pays it once. We are describing cost structures here, not promising an advantage in either direction. For the legal side of choosing a venue, see where prediction markets stand in your state, and the prediction markets hub is the front door to the rest of this section.
Prediction Market Fees FAQ
The cost questions readers ask most, answered from the venues’ published schedules.
How much does Kalshi charge per trade?
Kalshi’s taker fee is 0.07 times contracts times price times one minus price, rounded up to the cent. On 100 contracts that is $1.75 at a 50-cent price, $1.32 at 25 cents, and $0.34 at 5 cents. Some series carry different terms and a few charge nothing.
Does Polymarket charge fees now?
Yes. Polymarket US introduced taker fees exchange-wide effective July 1, 2026: 0.06 on the same price-times-one-minus-price shape, which is $1.50 per 100 contracts at coin-flip prices. It also pays makers a rebate rather than charging them.
Which venue is cheaper?
On standard markets and taker orders, Polymarket US charges less at every price point, and it pays makers instead of charging them. That is a fee-only comparison; market depth, funding options, and which markets each venue actually lists matter as much to the outcome of a trade.
Why does the fee change with the price?
Both formulas multiply by price times one minus price, which is largest at 50 cents and approaches zero at both extremes. The result is that uncertain contracts cost the most to trade and near-decided ones cost almost nothing.
Do I pay a fee when my contract settles?
No. Neither venue charges a settlement fee or a membership fee. The taker fee at the time of the trade is the whole cost on the platform side.
What is the cheapest way to fund an account?
A bank transfer. ACH deposits are free on both venues, while Kalshi adds a 2 percent processing fee on debit cards, including through Apple Pay and Google Pay. Your own bank may charge separately for wires.
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