This comparison was checked on 9 September 2026. It is product research, not legal, tax or trading advice. Availability and fees can change.
The three-column view
| Question | Kalshi | Polymarket US | Polymarket International |
|---|---|---|---|
| Product described here | US event contracts | Separate US event-contract product | International prediction-market interface and API |
| Account unit in current docs | US dollars | US dollars in documentation examples | USDC for trading and fees |
| Price formation | Participant orders in listed contracts | Participant orders in listed contracts | Participant orders in listed markets |
| General taker coefficient | 0.07 in the 7 July 2026 schedule | 0.06 from 1 July 2026 | Category-specific, including 0.04, 0.05 or 0.07; some markets have no taker fee |
| Maker treatment | General maker formula uses 0.0175 where applicable; some markets have special schedules | Published maker rebate coefficient of 0.0125 | Documentation says makers are not charged and eligible market fees fund maker rebates |
| Geography | Eligibility depends on Kalshi rules and law | US product has its own onboarding and eligibility | Geoblock page lists restricted and close-only jurisdictions |
| Settlement | Contract rules and designated outcome source | Contract rules and designated outcome source | Market resolution rules and platform process |
The coefficient row is not a flat percentage of the amount spent. Each platform’s formula includes the contract price and its complement, so fees generally peak near a 50-cent price and fall toward 0 or 1.
A fee example at 50 cents
For a simple comparison, assume a taker buys 100 contracts at $0.50.
Kalshi’s general taker formula is the ceiling to the next cent of 0.07 × contracts × price × (1 − price). The calculation is 0.07 × 100 × 0.50 × 0.50, or $1.75. Kalshi fee schedule, effective 7 July 2026
Polymarket US documents a taker coefficient of 0.06. The same inputs produce 0.06 × 100 × 0.50 × 0.50, or $1.50. Its schedule also documents volume-based taker rebates and a maker rebate formula. Polymarket US fee schedule
Polymarket International uses the same price-shape formula but assigns the rate by market category. At a 0.05 rate, 100 contracts at 50 cents produce a $1.25 fee; at 0.07, $1.75; at 0.04, $1.00. The live category table, not the brand name, determines the relevant rate. Polymarket International fees
These examples exclude funding, withdrawal, network, intermediary or third-party charges. Kalshi notes that certain rail fees can apply and that an introducing broker or futures commission merchant may charge separately. Polymarket says it does not charge deposit or withdrawal fees, while intermediaries can.
Kalshi: what the schedule says
Kalshi’s July 2026 schedule uses the 0.07 taker formula for the general case and 0.0175 for maker fees in markets where that maker charge applies. The PDF also contains nonstandard fee tables for named market groups. A user cannot safely apply the general formula to every contract without checking the market’s schedule.
The platform’s help material distinguishes the trading fee from movement of funds. That matters when comparing a trade made directly with one routed through another firm. The total customer cost can include a venue fee, a rail charge and a third-party charge.
Polymarket US: a separate rule set
Polymarket US has its own documentation domain and a fee schedule effective from 12am ET on 1 July 2026. The page shows USD examples, the 0.06 taker coefficient and a negative 0.0125 maker coefficient, which represents a rebate rather than a charge.
The schedule lists taker-volume rebate tiers. Those tiers should not be converted into a universal headline fee because the user first pays according to the formula and then qualifies under the stated volume conditions. The product documentation in force at the time of the trade controls.
Polymarket International: category-specific fees and USDC
International documentation says taker fees apply only to certain markets and makers are never charged. It lists 0.07 for crypto, 0.05 for sports and several other categories, 0.04 for finance, politics, technology and mentions, and zero for geopolitics at the check date. The fee is paid in USDC.
The international product’s geographic restrictions page is also a live operational document. It identifies blocked and close-only jurisdictions, including close-only treatment for the United States and United Kingdom at the time checked. A user should query the current page rather than rely on a copied country list. Polymarket geographic restrictions
“International” does not mean available everywhere. Nor does a restriction on one interface answer every legal question for a person or entity.
Funding and settlement are different comparisons
Funding asks how value enters the account. Trading asks how an order executes. Settlement asks what happens after the contract resolves. Combining them into one “speed” claim hides important differences.
For each platform, read:
accepted funding rails and any third-party fees;
order type, price increment and available depth;
contract collateral and maximum loss;
resolution source, timing and dispute language;
withdrawal rules after funds become available.
A blockchain transaction can settle on-chain while a market remains unresolved. A bank transfer can arrive after a contract’s best price has moved. The bottleneck depends on the stage.
Which one is cheaper?
There is no honest universal answer. At 50 cents and 100 contracts, the published general taker examples above can be compared directly. Away from 50 cents, the price term changes the fee. Market category, maker or taker status, volume rebates, funding method and third-party charges can reverse the result.
The better comparison is a worked ticket: same contract count, same price, same execution role and the exact current schedule. Then add the real funding and withdrawal path.
Which product fits which user?
Product fit starts with eligibility, not interface preference. After that, a participant can compare whether the desired contract exists, whether its resolution language is clear, how much depth is available and what the complete cost will be.
Kalshi, Polymarket US and Polymarket International all turn event questions into tradeable positions. They do not share one account, one fee model or one access policy. The correct comparison begins by naming all three.
