Kalshi vs. Polymarket Fees in 2026: What Traders Actually Pay

If you only compare prediction market apps by headline features, you miss the part that quietly eats returns: fees. In 2026, Kalshi and Polymarket still look similar from a distance—both let you buy event contracts tied to real-world outcomes—but their fee systems are not the same, and the differences matter most when you trade often, size up, or live near the middle of a market.

The short version: Kalshi charges transaction fees based on expected earnings and notes that some markets can carry different fee schedules, while Polymarket says most of its markets remain fee-free but now applies taker fees to all crypto markets launched on or after March 6, 2026, plus some sports markets such as NCAAB and Serie A. That means “Polymarket has no fees” is now outdated, and “Kalshi always costs more” is too simplistic to trust.

This guide breaks down what each platform actually says, where traders get tripped up, and which fee model is probably better depending on how you trade. For broader platform context, see PredictionMarkets.us’s guides to the best prediction market apps, our Polymarket guide, and the prediction market tax guide.

Kalshi vs. Polymarket fees: the fast answer

Here’s the cleanest way to think about it:

Platform	What the platform says	Where fees show up	Best source
Kalshi	Kalshi charges a transaction fee on expected earnings; some markets may have different fees, including special events. Maker fees can apply in some markets.	Trading fees depend on the contract and market-specific schedule.	Kalshi Help Center: https://help.kalshi.com/en/articles/13823805-fees
Polymarket	Most markets have no trading fees, but taker fees apply to all crypto markets started on or after March 6, 2026, plus NCAAB and Serie A markets.	Fee impact is biggest near 50% probability on fee-enabled markets.	Polymarket Docs: https://docs.polymarket.com/trading/fees

That table already kills one lazy SEO myth: there is no longer a universal answer like “Polymarket is free” or “Kalshi is expensive.” The honest answer is conditional, which is exactly why most comparison pages on this topic are sloppy.

How Kalshi fees work

Kalshi’s Help Center says the company “makes money by charging a transaction fee on the expected earnings on the contract,” and points traders to its fee schedule for the full math. Kalshi also explicitly says some markets have fees that differ from others, often because of special events such as elections, awards ceremonies, or large sporting championships. The same Help Center page says some markets can include maker fees, which apply to resting orders once they eventually execute, but not to canceled resting orders.

That matters because Kalshi’s fee system is not framed as a simple flat percentage on every trade. It is more contract-specific, and the platform itself tells traders to inspect the fee details inside the market UI before entering a position. If you assume all Kalshi markets have identical economics, you’re already one click behind.

• Kalshi Help Center, “Fees”: https://help.kalshi.com/en/articles/13823805-fees

How Polymarket fees work in 2026

Polymarket’s own documentation is much more explicit than a lot of third-party reviews. The docs say the “vast majority” of markets still have no trading fees, no deposit fees, and no withdrawal fees from Polymarket itself, though outside services like Coinbase or MoonPay may charge their own costs. But Polymarket now enables taker fees on specific market categories.

According to the March 2026 fee documentation, taker fees apply to:

• all crypto markets starting March 6, 2026
• NCAAB markets
• Serie A markets

Polymarket also publishes the fee shape. In crypto markets, the docs say the maximum effective fee rate peaks at 1.56% around 50% probability. In NCAAB and Serie A markets, the maximum effective rate peaks at 0.44% around 50% probability. The closer a contract is to the extremes—very near 0% or 100%—the lower the effective fee becomes.

Sources:

• Polymarket Docs, “Fees”: https://docs.polymarket.com/trading/fees
• Polymarket Docs, “Trading”: https://docs.polymarket.com/market-makers/trading

Why the 50-cent zone matters so much

If you trade prediction markets often, the middle of the book is where fee marketing starts to get bullshit-y.

Polymarket’s docs make clear that the effective fee is highest around 50% probability. That’s not random. The contracts around 50 cents are usually where traders do the most price discovery, where uncertainty is highest, and where active traders are likeliest to rebalance. In plain English: the place where many traders feel most comfortable is also the place where the fee burden is most noticeable on fee-enabled markets.

Kalshi’s system is different in structure, but the practical lesson is similar: you can’t judge cost by reading one homepage sentence. You have to inspect the actual market you want to trade.

This is also where trader behavior starts mattering more than brand preference:

• If you mostly take positions in near-even markets, fee sensitivity gets more important.
• If you mostly buy longshots or near-lock contracts, effective costs can look very different.
• If you rest liquidity rather than cross the spread, the experience changes again.

That’s why “Which platform is cheaper?” is the wrong first question. The better question is: “Cheaper for what kind of trade?”

Real market examples from March 10, 2026

Live market data makes the fee conversation less abstract.

On Polymarket, one of the biggest events by 24-hour volume on March 10 was Fed decision in March? with $11.8 million in 24-hour volume, and the “No change in Fed rates” market was trading around 98.9c YES. The same snapshot showed Will Crude Oil (CL) hit __ by end of March? at $4.7 million in 24-hour event volume. Those are the kinds of markets where traders may assume cost is negligible because the headline volume is huge—but on fee-enabled market types, your actual execution cost still depends on the specific market and where the probability sits.

On Kalshi, recent market data showed More tech layoffs in 2026 than in 2025? at $474.2K in 24-hour volume with pricing around 70/71c, while the Texas Republican Senate nominee event posted $428.9K in 24-hour volume. Kalshi’s own fee guidance says some special-event markets can have different fees, which is exactly why traders shouldn’t generalize from one category to every category.

Sources:

• PredictionMarkets.us market snapshot, March 10, 2026: our verified platform data
• Kalshi market links in the snapshot: https://kalshi.com/markets/kxlayoffsyinfo/more-tech-layoffs-in-20-26-than-in-2025 and https://kalshi.com/markets/kxsenatetxr/texas-republican-senate-nominee
• Polymarket event links in the snapshot: https://polymarket.com/event/fed-decision-in-march-885 and https://polymarket.com/event/will-crude-oil-cl-hit-by-end-of-march

Which platform is cheaper for casual traders?

For casual traders, Polymarket will often look cheaper on paper because most markets are still fee-free, according to its docs. If you make a few directional trades in markets without fees enabled, that’s hard to beat.

But there’s a catch: casual traders are exactly the people most likely to miss when a market is fee-enabled. If you wander into crypto or NCAAB and assume “Polymarket has no fees,” you’re trading off an outdated mental model.

Kalshi, meanwhile, is more upfront about the fact that fees exist and may differ by market. That can feel less sexy in a comparison table, but honestly it may produce fewer nasty surprises for traders who actually read what’s on screen.

My take: for true casual users who only place occasional trades and stay in mainstream markets, Polymarket can still be cheaper. For casual users who hate hidden nuance and want a more obviously regulated, inspect-before-you-click environment, Kalshi may feel cleaner even if the fee math is less headline-friendly.

Which platform is cheaper for active traders?

For active traders, the answer gets murkier fast.

Polymarket’s new taker fee structure matters most to traders who:

• hit lots of crypto markets
• trade around 50% probability
• rebalance frequently
• cross the spread instead of posting liquidity

That doesn’t make Polymarket bad. It just means the old “zero-fee” pitch is no longer enough for serious comparison work.

Kalshi’s fee model may be easier for some active traders to tolerate if they’re already adapting to market-specific economics and paying close attention to expected payout profiles. But because Kalshi can vary fees by market and special event, active traders still have to verify the exact contract before leaning on any rule of thumb.

The real winner for active traders is the platform whose market type matches the strategy. If you’re trading a fee-free Polymarket market, Polymarket can obviously be cheaper. If you’re grinding taker flow in fee-enabled crypto markets, that edge shrinks. If you’re trading Kalshi markets where the fee structure is visible and acceptable relative to your edge, Kalshi may make more sense.

That’s a boring answer, but boring answers are what keep traders from getting fleeced.

Fees are only one part of the cost

A lot of content in this category is obsessed with explicit fees because they’re easy to turn into tables. That’s fine, but it can also be dumb.

Your real trading cost also includes:

• spread width
• liquidity depth
• slippage
• settlement confidence
• access restrictions
• how fast news gets priced in

A “free” market with bad execution can cost more than a market with visible fees and tighter pricing. Reuters’ March 2 reporting on scrutiny around prediction markets tied to Iran-related contracts is also a reminder that platform context matters beyond raw fees. The piece notes that prediction markets have grown rapidly, are facing sharper legal and ethical scrutiny, and sit inside an evolving regulatory framework. That’s not a fee line item, but it absolutely affects trader risk.

• Reuters, March 2, 2026: https://www.reuters.com/world/middle-east/prediction-markets-scrutinised-over-iran-bets-2026-03-02/

So which fee model is better?

Here’s the blunt answer:

• Polymarket’s model is better if you mainly trade markets that remain fee-free and you want the lowest explicit cost on straightforward, occasional trades.
• Kalshi’s model is better if you prefer a U.S.-regulated platform that pushes you to inspect market-specific economics rather than lean on a blanket “free” narrative.
• Neither is automatically better if you trade often enough that liquidity, spread behavior, and market-type differences matter more than homepage slogans.

If you’re comparing these platforms seriously, stop reading affiliate pages that pretend one sentence settles the question. It doesn’t.

FAQ

Does Polymarket charge trading fees in 2026?

Yes, but not on every market. Polymarket says most markets are still fee-free, while taker fees now apply to all crypto markets created on or after March 6, 2026, plus NCAAB and Serie A markets. Source: https://docs.polymarket.com/trading/fees

Does Kalshi charge fees?

Yes. Kalshi says it charges a transaction fee on expected earnings and that some markets may have different fee schedules, especially for special events. It also says some markets can include maker fees. Source: https://help.kalshi.com/en/articles/13823805-fees

Is Polymarket or Kalshi cheaper?

It depends on the market and how you trade. Polymarket can be cheaper on fee-free markets, but fee-enabled crypto and sports markets change the math. Kalshi’s fees vary by contract and market type, so traders need to inspect the specific market before comparing costs.

Are there deposit or withdrawal fees on Polymarket?

Polymarket says it does not charge fees to deposit or withdraw USDC, though third-party intermediaries such as Coinbase or MoonPay may charge their own fees. Source: https://docs.polymarket.com/trading/fees

Do fees matter more for active traders?

Absolutely. If you trade often, rebalance near 50% probability, or take liquidity repeatedly, fee structure matters a lot more than it does for a casual trader placing a few one-off bets.

Final Verdict

The best 2026 answer to “Kalshi vs. Polymarket fees” is annoyingly nuanced: Polymarket is no longer universally fee-free, and Kalshi is not a simple flat-cost platform you can summarize in one lazy sentence. If you want the cheapest possible experience, you need to know the market type, not just the brand.

That’s why the smartest comparison workflow is simple: check the exact contract, verify whether the market has fees enabled, and then weigh that against liquidity and access. Anything less is just SEO theater.

For the bigger picture, keep browsing PredictionMarkets.us’s best prediction market apps, Polymarket guide, and prediction market tax guide.