Kalshi vs Polymarket is the central matchup in US prediction markets heading into 2027. Kalshi is the regulated, CFTC-licensed exchange where US residents trade event contracts in dollars; Polymarket is the crypto-native leader where traders worldwide have driven the largest contract volumes in prediction market history. The right venue depends on who you are, what you want to trade, and how you want to settle. Below is a direct comparison across the dimensions that actually matter: legality, markets offered, liquidity, fees, user experience, and the risk you take by using each.
The short answer
If you are a US resident who wants a legal, dollar-based account with federal oversight and clean tax reporting, Kalshi is the default. If you want the deepest politics and global-event liquidity, access to contracts US venues cannot list, and you are comfortable funding a crypto wallet with USDC on Polygon, Polymarket is unmatched. Many serious traders use both: Kalshi for compliance and economic contracts, Polymarket for scale and breadth.
Legality and regulation
Kalshi is a CFTC-regulated Designated Contract Market. That means its event contracts are legal financial instruments in all 50 US states, user funds sit with a qualified custodian, and the exchange is subject to the same federal oversight as any other US futures venue. After its 2024 federal court win over election contracts and the 2025 regulatory clarifications around sports event contracts, Kalshi has expanded aggressively while staying inside the US regulatory perimeter.
Polymarket operates as an offshore, crypto-based exchange. It settled with the CFTC in 2022 and formally blocked US users, though it is now pursuing US re-entry through its acquisition of QCX, a licensed designated contract market. For now, if you are a US resident, Polymarket is not a legal venue for direct access, and relying on a VPN to trade there is both against Polymarket’s terms and legally gray in the US. For non-US traders, Polymarket operates with far fewer restrictions and no KYC for small positions.
What you can trade on each
Kalshi offers a broad and growing menu of event contracts across US-friendly categories. Economics (CPI prints, Fed rate decisions, unemployment, GDP), politics (election outcomes, Supreme Court decisions, legislation), sports (NFL, NBA, MLB, college, UFC after the 2025 sports contract approvals), weather, pop culture, and crypto milestones are all represented. Contracts resolve on verifiable public data and settle in US dollars.
Polymarket’s catalog is wider and deeper on geopolitics, international elections, crypto markets, culture, and anything requiring global attention. If you want to trade the next French election, who will win Eurovision, OpenAI governance outcomes, or granular World Cup markets with hundreds of thousands of dollars of open interest, Polymarket is where the liquidity lives. Contracts are denominated in USDC and resolved by the UMA optimistic oracle.
Liquidity, fees, and execution
Polymarket historically wins on raw volume. The 2024 US presidential cycle saw billion-dollar notional volume on single contracts, and major geopolitical and crypto markets routinely post seven-figure daily turnover. Spreads on headline contracts are often one cent or tighter. The tradeoff is that long-tail markets can be thin, and resolution disputes rely on UMA token holders rather than a licensed clearing process.
Kalshi liquidity has grown rapidly through 2026, particularly on economic releases, elections, and newly approved sports contracts, but on most non-headline markets Polymarket still offers tighter books. Kalshi charges a per-contract fee based on probability and position size, disclosed up front; Polymarket charges no explicit trading fees but takes a maker-taker spread implicit in its order book and charges on-chain gas for deposits and withdrawals.
Fiat, crypto, and tax treatment
Kalshi takes US dollar deposits via ACH, debit card, and wire. Withdrawals go to the same bank account. The exchange issues 1099 forms at year end, and gains are typically taxed as ordinary income or short-term capital gains depending on your situation. For US traders who care about simple tax filing and an auditable paper trail, this is a meaningful advantage.
Polymarket is pure crypto. You fund your account with USDC on the Polygon network, trade in USDC, and withdraw in USDC. There is no fiat on-ramp inside the platform, no tax forms are issued, and tracking your cost basis across hundreds of trades falls on you. For international users, that friction is minor; for US tax residents, it is a serious operational burden on top of the legality issue.
Side-by-side comparison
| Dimension | Kalshi | Polymarket |
|---|---|---|
| Regulation | CFTC-regulated DCM | Offshore; US-blocked |
| Legal for US residents | Yes, all 50 states | No (direct access) |
| Currency | US dollars | USDC on Polygon |
| Deposits | ACH, debit, wire | Crypto only |
| Primary strengths | Economics, US politics, sports, weather | Global politics, geopolitics, crypto, culture |
| Headline liquidity | Strong on US events | Deepest overall |
| Fees | Transparent per-contract | No explicit fees; spread plus gas |
| Resolution | Exchange with regulated process | UMA optimistic oracle |
| Tax reporting | 1099 issued | Self-reported |
| KYC | Required | Minimal for small positions |
Who should use which
Choose Kalshi if you are a US resident who wants a legal, dollar-denominated account, clean tax paperwork, and strong markets on US economic data, elections, sports, and weather. The user experience is closer to a modern brokerage than a crypto exchange, and the regulatory moat only widens as other venues navigate the sports and political contract landscape.
Choose Polymarket if you are a non-US trader, you want unmatched depth on global politics and geopolitics, you want contracts US venues cannot list, or you specifically want to trade in crypto. Serious cross-border traders often arbitrage between Polymarket and Kalshi on the same event when both list it, because divergent user bases produce divergent odds.
For a broader view of the field, including Manifold, PredictIt, and newer entrants, see our full best prediction markets ranking, updated continuously.
Final verdict
Kalshi and Polymarket are not substitutes so much as complements. Kalshi has won the US regulatory race and is building the first mainstream, legal prediction market exchange in the country. Polymarket has won the global liquidity race and remains the deepest book for anyone trading beyond US-centric contracts. The decision isn’t which one is better in the abstract; it’s which one matches your residency, your trading focus, and your appetite for crypto operations.
Where to trade
Open a Kalshi account to trade US-regulated event contracts in dollars: Visit Kalshi.
If you are outside the US, Polymarket remains the deepest venue for global and crypto markets: Visit Polymarket.