Kalshi vs Polymarket: Which Prediction Market Is Right for You?

TL;DR

• Kalshi is a CFTC-regulated exchange (a Designated Contract Market since November 2020) built for US traders funding in dollars. Polymarket is the larger global crypto-collateral market, funded in USDC, with deeper liquidity outside the US.
• As of late 2025, Polymarket is no longer fully blocked in the US: it acquired a CFTC-licensed exchange (QCX, for $112 million) and relaunched as "Polymarket US" in beta in November 2025. That US arm is real but still much smaller than the main international platform ($1.3B vs. $9B in monthly volume as of April 2026).
• Kalshi carries the deeper book on US sports and domestic political/economic contracts; Polymarket International carries the deeper book on global politics, crypto, and culture. Kalshi handled roughly 83% of CFTC-regulated prediction-market volume in July 2026.
• Both charge a fee that peaks at a 50-cent contract price and shrinks toward the extremes, not a flat rate. Polymarket's makers pay $0; Kalshi's maker fee is 25% of its taker fee.
• The two also differ in custody model: Kalshi holds customer cash in FDIC-insured bank accounts as a centralized, CFTC-regulated custodian. Polymarket's international platform is non-custodial, settling on-chain through audited smart contracts and a token-voting oracle, a different risk trade-off, not a better or worse one on its face.

That's the shape of the comparison. Below: how we compared them, and every place they actually differ, regulation, fees, liquidity, custody, disputes, verification, and the mobile experience, followed by a clear verdict on which fits which trader.

How Did We Compare Kalshi and Polymarket?

Methodology, stated plainly: this comparison draws on each platform's own published fee schedules, help-center docs, and CFTC filings (linked inline and in Sources below), cited third-party volume and dispute data, and PredictionHero's own live cross-platform tracking, which prices the same event on both exchanges at once.

Data points are dated where they can go stale, since fee schedules, volume rankings, and legal status all shift month to month. This page was last reviewed July 30, 2026; if you're reading it later, check the linked primary sources for anything that looks off, and confirm current access directly with each platform before funding an account.

How Do Kalshi and Polymarket Compare at a Glance?

Both platforms run on the same binary logic. A Yes contract pays $1 if the outcome happens and $0 if it doesn't. The two sides of a market sum to roughly $1.00 before fees, so if Yes trades at 63 cents, the market is pricing a 63% chance. If you want the mechanics explained from scratch, we cover it here. That mechanic is identical on both exchanges. What differs is who can access which product, how it's funded, who holds custody of your position, and how deep the order books run.

Is Polymarket Actually Legal in the US Now?

This is the part most comparisons get wrong by not updating it, so it's worth walking through in order.

In January 2022, the CFTC charged Polymarket (then Blockratize Inc.) with offering unregistered event contracts to US users. The company settled for a $1.4 million civil penalty, wound down the noncompliant contracts, and blocked US customers, a ban that held for close to three years.

That changed starting in 2025. Polymarket closed a $112 million acquisition of QCX LLC, a CFTC-licensed derivatives exchange and clearinghouse, in July 2025. The CFTC issued QCX a no-action letter in September 2025 and an Amended Order of Designation in November 2025, and Polymarket US opened in beta to select American users on November 12, 2025, with real-money trading. In April 2026, Polymarket filed with the CFTC seeking approval to let US users trade directly on its primary international exchange rather than the separate, smaller US product.

The practical result: Polymarket US is a real, CFTC-regulated product, not a workaround, but it's a distinct and considerably smaller market than the offshore Polymarket.com platform most people mean when they say "Polymarket." As of April 2026, Polymarket US carried about $1.3 billion in monthly volume against roughly $9 billion on Polymarket International in the same period. It also requires full identity verification, unlike the international platform.

If you're a US trader evaluating Polymarket today, know which product you'd actually be signing up for, and confirm current state availability directly on Polymarket, since access is still expanding and not identical everywhere.

Kalshi's federal position is more settled by comparison: its core markets have operated under CFTC designation since November 2020 with no equivalent access gap. Its sports contracts specifically are a separate, ongoing state-by-state legal fight. We cover that dispute in full here. That fight doesn't touch Kalshi's broader catalog.

Which Platform Actually Has the Bigger Market?

Kalshi and Polymarket International are both large and both growing, but they aren't growing evenly. Kalshi posted $17.91 billion in notional volume in May 2026, its ninth consecutive monthly volume record, up 21% from April's then-record $14.81 billion. Polymarket posted $7.08 billion over the same month, down 21% from its March 2026 peak of $10.57 billion. Across CFTC-regulated prediction-market exchanges specifically, Kalshi accounted for roughly 83% of notional volume in July 2026.

The two platforms aren't competing head-on for the same volume, though. Sports contracts have made up roughly 80% of Kalshi's trading volume since July 2024, while sports is closer to 39% of Polymarket's. Polymarket's strength sits in politics, crypto, and fast-moving global or cultural events, categories where Kalshi's US-retail-heavy base doesn't concentrate the same way. Neither platform's lead is universal. It depends which category you're looking at.

Do Kalshi and Polymarket Price the Same Event Differently?

The reason to check both platforms isn't theoretical. Contracts on the same real-world event routinely trade at different implied probabilities on each one, because the traders on each platform are different. Kalshi's base is domestic and reachable without a crypto wallet. Polymarket's base is global and crypto-native, weighted toward traders who already hold digital assets and think in on-chain terms.

That split shows up in practice. On a major macro event like a Federal Reserve rate decision, Kalshi's US-heavy order flow and Polymarket's international, crypto-funded order flow can settle on different implied probabilities for the identical outcome before arbitrage traders close the gap. PredictionHero tracks both prices in one view specifically so you can see that gap directly instead of guessing at it from a single platform.

Liquidity plays into this too. A thinly traded contract on either platform can swing several points on a single large position, since there isn't enough opposing volume to absorb it. A deeply traded contract barely moves on the same size trade. Kalshi tends to carry the deeper book on domestic political and economic events; Polymarket tends to carry the deeper book on global and culture-driven markets. That's a structural pattern tied to where each platform's volume concentrates, not a fixed rule, which is exactly why a same-event comparison is worth checking before assuming one platform's price is the "real" one.

Which Prediction Market Is Cheaper: Kalshi or Polymarket?

Neither charges a flat percentage. Both use a formula that charges more on a contract near a 50-cent price, where genuine uncertainty exists, and less near the extremes, where the outcome is close to settled.

Kalshi's taker fee is roughly 7¢ × price × (1 − price) per contract, peaking at about 1.75¢ per contract at 50 cents. Its maker fee (for resting limit orders) is 25% of the taker fee, which often rounds to close to nothing on small orders.

Polymarket's fee schedule, effective exchange-wide from July 1, 2026, caps the fee per 100 shares by category: $1.00 for politics, finance, tech, and mentions; $1.25 for sports, economics, culture, and weather; $1.75 for crypto; and geopolitical markets are entirely fee-free.

Like Kalshi's, the fee peaks at a 50-cent share price and falls off toward the extremes, so a contract trading near 85 or 90 cents costs a fraction of the headline rate. The bigger structural difference: Polymarket's makers pay $0 in fees and can earn a rebate funded by taker fees, while Kalshi's makers still pay a reduced fee rather than none.

Neither platform charges for depositing or withdrawing in its native funding method (ACH for Kalshi, USDC for Polymarket), though Kalshi's debit-card funding carries a roughly 2% processing fee and Polymarket's crypto transfers carry standard Polygon network gas costs, typically a small fraction of a dollar per transaction.

If you're trading actively rather than holding to settlement, check the current schedule on the specific contract before you enter; both platforms update these numbers independently, and a figure printed in an article goes stale.

How Do Deposits and Withdrawals Actually Compare?

Kalshi funds in dollars: ACH bank transfer, debit card, or wire, no crypto wallet required. That's the more familiar path if you're coming from traditional finance.

Polymarket funds in USDC. You can buy it directly inside the platform through a built-in fiat on-ramp (card or bank, via third-party processors), which is the simplest path but the most expensive, typically a few percent above market rate plus card fees.

The cheaper path, if you're comfortable with an extra step, is buying USDC on a mainstream exchange like Coinbase and sending it to your Polymarket wallet over the Polygon network, where gas costs run a small fraction of a dollar per transaction rather than the higher fees typical of the Ethereum mainnet.

Withdrawals work the same way in reverse: off-ramp through the built-in provider for convenience, or send USDC to an exchange account yourself for a lower total cost. Polymarket US, being a more traditional intermediated exchange, is expected to move toward direct fiat funding over time, but as of this writing its funding flow still runs through the same crypto rails as the international platform.

How Do Kalshi and Polymarket Handle Custody and Security?

This is a real structural difference that changes what kind of risk you're actually taking on.

Kalshi is a centralized custodian. It holds customer cash in segregated accounts at FDIC-insured banks, including JPMorgan Chase and Bank of New York Mellon, separate from its own operating capital, the same protection model a traditional futures brokerage uses. The FDIC insurance covers the bank holding the funds, not Kalshi itself as a company, but the segregation requirement is real and CFTC-enforced.

Polymarket's international platform is non-custodial. Your USDC and outcome tokens sit in your own wallet, secured by your own private key, and trades execute through audited smart contracts on Polygon. Polymarket itself never takes possession of your funds. That removes one kind of risk (a custodian losing or misusing your cash) and introduces another: you're responsible for your own wallet security, and smart-contract risk, however well-audited, isn't zero.

Polymarket US, as a CFTC-regulated intermediated exchange, is expected to carry a more traditional custody arrangement closer to Kalshi's, though the platform hasn't published the same level of public detail on that arm yet.

Neither model is strictly safer. A centralized custodian gives you a regulator to call and a bank behind your cash, with the tradeoff of trusting that custodian's operations. A non-custodial model removes the custodian entirely, with the tradeoff of full personal responsibility for wallet security and smart-contract risk. Which you prefer says more about your own risk tolerance than about either platform's legitimacy.

How Do the Two Platforms Handle Disputed Settlements?

Every market eventually has to resolve, and how each platform handles a contested resolution is one of the more revealing comparisons you can make.

Kalshi resolves markets centrally, against its own published contract terms, under CFTC oversight. That model was tested in January 2026, when some traders holding winning positions on certain NFL contracts were initially paid only their original stake rather than the full $1 settlement value, after Kalshi said the underlying markets had closed prematurely.

Kalshi reversed the decision under user backlash and paid the full amount owed. A separate class-action complaint over a different contract clause was also filed around the same period. The episode showed a real operational miss, and a correction once it surfaced publicly.

Polymarket resolves disputed markets through UMA, an optimistic oracle where a proposer posts a bond with an outcome, and token holders can dispute and vote if they disagree within a challenge window. That structure is transparent and decentralized by design, and it's still maturing: a few notable cases have tested it in public, including a roughly $79 million market on whether Ukrainian President Volodymyr Zelenskyy would wear a suit, and a March 2025 contract on a Trump-Ukraine minerals deal where a single large token holder's vote proved decisive in a close call.

A separate, high-dollar 2026 case around a Strategy Bitcoin sale market drew similar attention. These are the kind of growing pains a young, decentralized governance model works through in public, and they're part of why UMA and Polymarket have continued adjusting bond sizes and dispute mechanics over time.

Neither approach is without trade-offs. Kalshi's centralized model concentrates the resolution decision in one company, with a federal regulator as recourse if it gets it wrong; the January 2026 episode showed both the miss and the correction.

Polymarket's token-voting model removes a central decision-maker, which cuts out a single point of failure but means a resolution can hinge on how concentrated the vote turns out to be in any given dispute, as the minerals-deal case showed. Read the specific resolution rules on any contract you're trading on either platform, especially around edge cases, rather than assuming either model catches every dispute cleanly.

Do Kalshi and Polymarket Require ID Verification?

Kalshi requires full identity verification, government-issued ID and standard KYC, for every account, consistent with its status as a regulated US exchange.

Polymarket's international platform historically has not required KYC to trade through a connected wallet, part of what makes it feel closer to native crypto infrastructure than a traditional brokerage. Polymarket US is different: as a CFTC-regulated entity, it requires full identity verification before you can trade, putting it on the same footing as Kalshi rather than the international platform it's affiliated with.

Which Has the Better Mobile Experience?

Kalshi has run established native apps on both iOS and Android for some time, and mobile trading is a normal part of how its retail base uses the platform.

Polymarket has been catching up specifically on this front. Its iOS app dropped its US waitlist and opened to all American users in May 2026; its Android app, as of this writing, is still rolling out gradually behind a waitlist rather than being fully public. If mobile access matters to you today rather than in a few months, that gap is worth knowing before you pick a primary platform.

Can You Use Both Kalshi and Polymarket?

Yes, and if you're serious about reading what markets are actually pricing, using both is the more defensible approach rather than picking one. Kalshi requires a US bank account or debit card and standard identity verification. Polymarket International requires a crypto wallet funded in USDC and no KYC; Polymarket US requires ID verification and is working toward more traditional funding.

There's no rule against holding accounts on more than one, and they rarely compete for the exact same trader, since the funding method and verification requirements differ so much.

Which One Is Right for You?

If you're a US-based trader who wants a regulated venue, a bank transfer, and no crypto wallet, Kalshi is the straightforward choice. Its CFTC status means federal oversight preempts most state-level restrictions on its core markets, which is why it operates nationwide while Polymarket's international platform still can't fully reach US retail traders directly. You can sign up for Kalshi here.

If you're comfortable holding and moving crypto and you want the largest global market with the deepest liquidity on politics and current events, Polymarket International is the stronger pick, with the caveat that most US retail traders still can't access it directly and should look at Polymarket US instead. Its user base is international, which means non-US political and cultural events often get priced with more precision than on a US-only platform. You can check Polymarket here.

Neither is strictly better. They're built for different traders in different jurisdictions, funding in different currencies, with different custody models. The honest answer to "Kalshi or Polymarket" is that most serious market-watchers end up checking both, because the gap between them, in price and in structure, is often where the more interesting read sits.

So, Kalshi or Polymarket: What's the Verdict?

For US residents who want a fully regulated, dollar-funded on-ramp today, Kalshi wins on access. For global reach, market depth, and category breadth, Polymarket's international platform still wins, with its own newly regulated US arm as a smaller, growing third option worth watching rather than dismissing.

If you're trying to understand what a market is actually pricing rather than just place a position on one venue, the better move isn't picking a side. It's comparing both, along with Limitless, Predict.Fun, and Opinion, the other three platforms PredictionHero tracks.

What Other Prediction Market Platforms Are Worth Knowing?

Kalshi and Polymarket dominate volume, but they aren't the only venues, and treating them as the whole market means missing real pricing divergence elsewhere.

Limitless Exchange runs on-chain with its own token and leans into shorter-duration contracts. If you want to see how a market prices an event closer to resolution, Limitless is worth a look.

Predict.Fun is built on BNB Chain and does something neither Kalshi nor Polymarket does: collateral sitting in an open position can earn yield while it's parked there. That draws traders who want their capital working even while a position sits open.

Opinion was built for macro trading, things like rate decisions, inflation data, and broader economic releases, with sports and politics sitting alongside that focus rather than leading it. Its pricing is a useful cross-check against the sports- and politics-heavy consensus on the other four platforms. Visit Opinion.

Sources

• CFTC. Order against Blockratize Inc. d/b/a Polymarket, January 3, 2022 ($1.4M penalty, US customer ban).
• PR Newswire. "Polymarket Acquires CFTC-Licensed Exchange and Clearinghouse QCEX for $112 Million." July 21, 2025. prnewswire.com
• CoinDesk. "U.S. CFTC Gives Go-Ahead for Polymarket's New Exchange, QCX." September 3, 2025. coindesk.com
• CCN. "Polymarket Quietly Returns to the U.S., Here Is What's New." ccn.com
• PYMNTS. "Polymarket Seeks End to CFTC Trading Ban." 2026. pymnts.com
• Polymarket US. "Fee Schedule," effective July 1, 2026. docs.polymarket.us/fees
• Polymarket Help Center. "Trading Fees." help.polymarket.com
• Polymarket. "Polymarket 101" (custody and smart-contract model). docs.polymarket.com
• Polymarket US. "KYC Verification Flow" (partner docs). docs.polymarket.us
• Kalshi. "Fee Schedule," updated July 7, 2026. kalshi.com/docs/kalshi-fee-schedule.pdf
• CasinoBeats. "Kalshi Reverses Policy on Unpaid NFL Winning Predictions." January 7, 2026. casinobeats.com
• The Defiant. "$60M Polymarket Dispute Over Strategy's May Bitcoin Sale Puts UMA's Token-Voting Oracle on Trial." thedefiant.io
• Webopedia. "Why Is Polymarket's UMA Controversial?" (Zelenskyy-suit and Ukraine minerals-deal disputes). webopedia.com
• Sportico. "How Kalshi, Other Prediction Markets Performed at 2026 World Cup." sportico.com
• DeFi Rate. Aggregated Kalshi/Polymarket volume data. defirate.com

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