Polymarket vs Kalshi Fees: Compare the Total Cost
Opening and fee comparison checked: November 6, 2026. Other examples last reviewed October 24, 2026.
Polymarket.com and Kalshi do not have one universal fee you can compare as a percentage of profit. Polymarket.com charges takers on certain market categories and does not charge makers. Kalshi varies charges by market, and maker fees can apply. Check the current schedule for the specific order.
Compare the same contract quantity and price, then record entry and exit fees, funding, conversion and withdrawal costs. Use actual execution prices when calculating principal and proceeds, so spread or slippage is not counted twice.
The Polymarket examples in this guide refer to international Polymarket.com. Polymarket US is a separate product with a separate fee schedule. Do not transfer international rates to its app.
This guide explains the math with hypothetical examples, without using a live exchange rate or promising returns. It is not authorization to trade: in the documentation reviewed on October 24, 2026, Polymarket lists Brazil as close-only, which means users cannot open new positions. See the official geographic restrictions. International eligibility at Kalshi does not equal authorization under Brazilian law either.
Polymarket.com vs Kalshi: fee comparison at a glance
| Product | Maker orders | Taker orders | Check before calculating |
|---|---|---|---|
| Polymarket.com (international) | No maker trading fee under the current documentation | Rates vary by category; use quantity × rate × price × (1 − price) | Current market category, fee rate and any intermediary costs |
| Kalshi direct exchange | Maker fees apply to some markets | General formula uses M × 0.07 × quantity × price × (1 − price), with schedule-specific rounding | Current multiplier, exceptions and applicable maker schedule; broker charges can differ |
For a hypothetical purchase of 100 contracts at $0.60, the principal is $60.00 on either venue. A Polymarket.com market with a 0.04 taker rate adds $0.96; Kalshi's general schedule with M = 1 adds $1.68. The resulting outlays are $60.96 and $61.68 before other costs. These assumptions are examples, not equivalent live contracts or a universal cheapest-platform ranking.
Sources checked November 6, 2026: Polymarket.com fees and Kalshi's official fee guidance and linked schedule. The schedule reviewed is dated July 7, 2026. Follow the current schedule linked by Kalshi and verify the order ticket before reusing the coefficients.
What goes into the total cost?
A transaction can generate costs at different stages. Combining those stages creates misleading comparisons and can cause an order to exceed the available balance.
| Stage | What to check | How to record it |
|---|---|---|
| Currency conversion | Effective rate, spread, and intermediary fee | Amount paid in reais and balance received in the reference currency |
| Deposit | Accepted method and any provider cost | Amount sent and amount credited |
| Contract purchase | Quantity, execution price, and applicable fee | Principal and entry fee separately |
| Early exit | Execution price and possible new fee | Gross proceeds minus exit fee |
| Resolution | Payout defined by the rules | Proceeds per winning or losing contract |
| Withdrawal | Withdrawal, conversion, and intermediary costs | Balance withdrawn and final amount received |
There is no universal percentage for foreign exchange, networks, or intermediaries. A reproducible comparison must identify the provider, time, and transaction size. “No platform fee” does not mean “no total cost.”
How to interpret Polymarket fees
The official Polymarket fee documentation uses the following formula for markets covered by the fee structure:
fee = quantity × fee rate × price × (1 − price)
Price must be expressed from zero to one. Therefore, 60 cents enters the formula as 0.60, not 60. The fee rate must come from the current market; it is not the final percentage of principal. The documentation reviewed on October 24, 2026 says makers are not charged, while takers pay on certain market categories. A limit order that executes immediately is not automatically a maker order.
Current fee rates vary by category. Polymarket lists 0.07 for crypto, 0.05 for sports, economics, culture, weather and general markets, 0.04 for finance, politics, mentions and technology, and zero for geopolitics. Combos have their own rate. Always verify the market details because the schedule can change.
Hypothetical example: 100 contracts at $0.60
Assume 100 contracts with a $1 final payout and a fee rate of 0.04. This is an arithmetic exercise, not an available or recommended order. Values are shown in dollar equivalents for readability and do not simulate conversion from reais.
- Principal:
100 × 0.60 = $60.00. - Entry fee:
100 × 0.04 × 0.60 × 0.40 = $0.96. - Acquisition cost:
60.00 + 0.96 = $60.96.
In this example, the rate is 0.04, but the fee equals 0.96 ÷ 60 = 1.6% of principal. It is not 4% of principal or 4% of profit. Changing the price changes this relationship.
If all 100 contracts win and are held through resolution, gross proceeds are $100.00. The difference from acquisition cost is $39.04 before additional transfer or conversion costs. If they lose, proceeds are zero and the acquisition loss is $60.96. Neither outcome is certain in advance.
Why dividing the balance by price is not enough
Now assume an available balance of $99.50 under the same price and fee assumptions. Each contract requires 0.60 + 0.04 × 0.60 × 0.40 = $0.6096, before any operational rounding differences.
- 163 contracts: $97.80 principal; calculated fee of $1.5648; total of $99.3648.
- 164 contracts: $98.40 principal; calculated fee of $1.5744; total of $99.9744.
The second quantity exceeds the balance. The first fits under these assumptions, but actual execution still depends on price, depth, quantity rules, and rounding. Dividing only 99.50 ÷ 0.60 ignores the fee and sizes the budget incorrectly.
The same care applies when a trade fills in several parts. If fills occur at different prices, calculate principal and fee for each fill, then add them. Using only the best price displayed can underestimate the outlay.
Example of a sale before resolution
Suppose the same 100 contracts are later sold at $0.55, with a hypothetical 0.04 fee rate on exit. Gross proceeds are $55.00. The calculated fee is 100 × 0.04 × 0.55 × 0.45 = $0.99. Net sale proceeds are $54.01.
Compared with the initial $60.96 acquisition cost, the result is a $6.95 loss before other costs. The loss reflects both the price change and the two fees. Do not subtract an estimated spread again if you already use actual execution prices; that would count the same price effect twice.
How to check Kalshi fees
Kalshi's official fee help center states that charges vary by market and that maker fees can apply in some cases. It is not correct to apply one formula or fee from one contract to every other contract.
Before estimating cost, record the applicable schedule, date, market, and final order value. If the schedule cannot be confirmed, keep the fee as a pending input instead of assuming zero. The help page links to the current fee schedule. If the server limits access, do not present an old copy as the current schedule.
A valid calculation without inventing the fee
If 100 contracts cost $0.60 each and the displayed fee is F, the outlay is $60.00 + F. If a favorable resolution pays $1 per contract, the gross difference after that fee is $40.00 − F. With an unfavorable resolution, the acquisition loss is $60.00 + F.
This model keeps the schedule-dependent input explicit. It does not claim Kalshi charges the same as Polymarket. For a real comparison, use questions with equivalent rules and comparable quantities; similar prices on different events do not produce a useful cost comparison.
Makers, takers, and limit orders
An order that rests in the book and provides liquidity has a different role from one that executes against available quotes. These roles are commonly called maker and taker. Order type alone does not determine the role: a limit order can consume liquidity immediately.
Do not turn the possibility of providing liquidity into advice to “always avoid fees.” An order that does not execute does not create the intended position. It can fill later, only partially, or after the information set has changed. Incentive programs also have their own criteria; they are not guaranteed discounts or returns.
Read the maker-taker model guide to distinguish order books, spreads, and execution.
Costs the platform fee table does not solve
Conversion between reais and the reference currency
To evaluate a conversion, divide the reais actually paid by the balance credited. Then record separately any fees not already embedded. An advertised quote does not necessarily equal the transaction's effective exchange rate.
At withdrawal, check whether a fee applies to the entire converted balance, not only the profit. For example, a hypothetical 1% proportional fee on a $120 withdrawal applies to $120. Applying it only to $20 of profit would understate the cost. This percentage is illustrative, not a provider quote.
Collateral and transfers
Current Polymarket documentation describes pUSD as collateral associated with USDC. Do not assume old network or asset instructions remain valid. Stablecoins, contracts, and intermediaries carry their own risks; displaying values in dollars does not guarantee conversion without loss or eliminate technical risk.
At Kalshi, deposit and withdrawal methods can depend on the account and location. Check the transfer documentation. General international availability does not confirm that a Brazilian resident is authorized to trade.
Spread, depth, and slippage
Spread is the distance between the best bid and ask. Depth is the available quantity at each level. Slippage is the difference between the reference price and the execution price. Historical volume does not guarantee sufficient depth now.
A larger trade may move through several book levels. To estimate principal, multiply the quantity at each level by its price and add the results. Add applicable fees without mixing trading costs with currency conversion. The slippage guide explains this calculation in more detail.
Checklist for a reproducible comparison
- Identify the product, legal entity, and permitted jurisdiction.
- Record the market, payout rules, and fee schedule date.
- Separate quantity, price, principal, and trading fee.
- Account for partial fills and different prices.
- Distinguish an early sale from resolution and withdrawal.
- Record conversion and intermediaries without duplicating embedded costs.
- Calculate favorable and unfavorable scenarios, not only the possible gain.
This framework can also be used to study markets without taking positions. For platform differences, read the Kalshi or Polymarket comparison. Our coverage of the Kalshi and Polymarket restrictions in Brazil treats eligibility separately.
Frequently asked questions
Is the fee a percentage of profit?
Do not assume that. A trading fee can apply even when the trade ends at a loss. Verify the formula and schedule for the product and market.
Does a limit order always avoid fees?
No. It can execute immediately against the book and consume liquidity. Rules for liquidity-providing orders also differ between platforms and markets.
Does no trading fee mean zero cost?
No. Currency conversion, intermediaries, and execution can change the final amount. Record actual costs instead of inventing a universal range.
How do I separate proceeds from profit?
Proceeds are what a sale or resolution pays. Result is proceeds minus acquisition cost and other applicable costs. A winning $1 contract does not automatically generate $1 of profit.
Does the example authorize Brazilians to trade?
No. It is a mathematical simulation. Geographic restrictions and Brazilian rules must be observed; Polymarket's current documentation lists Brazil as close-only.
Conclusion
A comparison of Polymarket and Kalshi fees must state its assumptions and preserve the units. Principal, fee, payout, and result are different numbers. Access eligibility comes before the calculation; after that, comparison quality depends on executable prices and verifiable costs.
Choosing a platform, order type, or lower-fee market does not guarantee a gain. Use the calculation to understand risk and check the budget, not as a promise of returns.
