The lowest advertised fee doesn’t always produce the lowest-cost trade. A useful prediction market comparison also considers the spread, available order-book depth and rules that determine payouts. Compare fees, liquidity, regional availability and withdrawals against the trade you intend to place.
Start with the product itself. In the simple binary contract Interactive Brokers describes, a correct position pays USD 1.00 per contract, while an incorrect position has no value. The CFTC’s example makes the risk clear: traders who predict incorrectly lose their investment. Even on a regulated venue, a losing position can cost you its purchase price plus any fees paid.
Check eligibility before comparing costs. The table below covers U.S. products priced in USD. Access to a website doesn’t establish that you’re eligible to trade a particular contract where you live.
Compare the Full Cost of One Trade
A maker places an order that rests on the order book until someone else matches it. A taker places an order that matches an available order immediately. The charge depends on how the order executes: a limit order that matches an existing offer fills as a taker and can incur taker fees.
Trading charges. The table shows published entry charges for a standardized order, based on schedules available on October 16, 2026. These examples cover different venues and access routes, so they aren’t all-in quotes for identical contracts. They exclude rebates, special-product schedules, funding costs and any additional intermediary charges.
Illustrative entry fees for 100 contracts at $0.50
| Venue (U.S. product) | Published charge | Execution type and exclusions |
| Kalshi, standard schedule | $1.75 | Taker, multiplier 1, under the July 7, 2026 fee PDF; markets with other multipliers or maker fees differ |
| Polymarket US, standard schedule | $1.74 | Taker, 0.0695 coefficient; excludes special-product schedules and rebates |
| ForecastEx contracts via Interactive Brokers, direct-client schedule | $1.00 | $0.00 broker commission plus $0.01 per contract exchange fee (100 × $0.01); commission rates may vary by program or arrangement |
Check the schedule for your specific market and access route before placing an order. Kalshi charges maker fees in some markets, so a resting order isn’t always free. Polymarket International has a separate schedule under which makers pay no trading fees and taker charges vary by market category. That schedule does not apply to the U.S. product.
The rest of the bill. Selling before settlement is another trade and may carry its own charge. Holding to resolution on Kalshi adds no separate settlement fee under its published schedule. Also account for the spread, any funding or currency-conversion costs, and any withdrawal charge.
List each cost for the same hypothetical order, and calculate an early-exit scenario separately from holding to settlement. Best prediction markets rankings can shorten that groundwork. Prediction Markets Best, for example, lists each platform’s published fee formula alongside its product type, regional availability and editor score in one table, which gives you a starting point for this worksheet. Confirm the applicable charges in the current product schedule before relying on the total.
Check Liquidity at Your Order Size
The bid is the highest price a buyer currently offers; the ask is the lowest price a seller currently accepts. The spread is the gap between them, a trading cost separate from published fees. Depth is the quantity available at each price. Past trading volume doesn’t tell you how much is available now at the price you want.
Inspect the book. A hypothetical round trip shows the cost. Buy 100 contracts at a $0.52 ask and you pay $52. Sell them immediately at an unchanged $0.49 bid and you receive $49. The $3 difference is the spread cost before any explicit fee, assuming enough contracts are available on both sides.
If the best price lacks enough quantity to fill your order, the remainder may fill at worse prices. The displayed quote therefore doesn’t establish your average cost. Compare contracts with matching event wording and deadlines, read both sides of the order book, and estimate the average price for your full quantity.
Plan the exit. An early sale can fetch less than the displayed quote when buying interest is thin, a common problem because prediction market liquidity tends to concentrate in headline events and leave long-tail contracts shallow. Being able to submit a sell order doesn’t guarantee the price you want. A limit order controls the price you’ll accept but may remain unfilled. Decide beforehand whether you can hold to settlement if your planned exit isn’t available.
Read the Rules Before Risking Money
Eligibility. Identify the operator and product behind a brand name. Polymarket International lists the United States as a blocked country, so U.S. users can’t place orders there. Its separate U.S. product has different access rules, and individual contracts can impose additional participation restrictions.
Regional labels on comparison sites are research aids, not legal advice. In the United States, federal and state authority over sports-related contracts remains disputed. The advisory CFTC staff issued on March 12, 2026 is staff guidance, not a new statute or a final resolution of those disputes.
Settlement. Read the contract rules rather than relying on the market headline. Check the named resolution source, cutoff time and time zone, cancellation provisions, dispute procedure and payout timing. Similar headlines can describe contracts with different settlement terms, which makes them unsuitable for a direct price comparison.
Using comparison research. Look for a comparison site that distinguishes document research from funded-account testing and leaves unassessed criteria unrated. The comparison referenced above does both, and it provides information without operating an exchange or holding customer funds. Treat its scores as editorial assessments rather than independently validated performance results, and check whether a review includes a dated account test.
If you want forecasting practice without a cash payout, Manifold’s mana markets use play money that cannot be converted to cash.
Conclusion
Choosing a prediction market comes down to the cost and risk of the specific trade you plan to place, not the headline fee. Price the full order, including taker or maker charges, the spread and any exit or withdrawal costs. Check the order book at your size and plan how you’ll leave the position. Then confirm that you’re eligible for the product and that you understand how the contract settles. A venue that holds up on all four counts is a better choice than one that simply advertises the lowest rate.
FAQs
How are prediction market trading fees calculated?
Many venues charge takers on a curve that peaks when a contract trades at 50 cents and falls toward the extremes. Under Kalshi’s standard schedule, buying 100 contracts at 50 cents as a taker costs $1.75. Resting maker orders often pay less or nothing, although some markets do charge makers.
What is the difference between a maker and a taker order?
A maker order rests on the order book until another trader matches it. A taker order matches an existing order immediately. The same limit order can be either one, depending on whether it fills against a resting order the moment you submit it.
Why can the spread cost more than the published fee?
The spread is the gap between the best bid and the best ask, and you pay it every time you cross it. In a thin market, buying at the ask and selling straight back at the bid can cost more than the exchange fee on the same trade.
Can U.S. residents trade on Polymarket?
Not on the international site, which blocks U.S. users from placing orders. Polymarket US is a separate CFTC-designated exchange with its own fee schedule and access rules.
Is there a fee for holding a contract until it settles?
On Kalshi, no. Its published schedule lists no separate settlement fee. Other venues set their own terms, so check each schedule, along with any withdrawal or funding charges.
