Polymarket vs Kalshi: the definitive comparison
Polymarket vs Kalshi, side by side. Fees, markets, regulation, UX, custody, taxes. The short answer: Kalshi if you're in the US, Polymarket if you're not. Here's the full reasoning.
The thirty-second summary
- Kalshi is a federally-regulated Designated Contract Market in the United States. It's the closest thing to Polymarket that's legal for Americans.
- Polymarket is a decentralized prediction market on Polygon, used globally by non-US residents.
Both let you trade YES/NO shares on real-world events. Both settle winning contracts at $1 and losing contracts at $0. Both have order books, mobile apps, APIs for algorithmic traders.
The differences matter, and they're more than cosmetic.
Platform comparison at a glance
| Feature | Polymarket | Kalshi |
|---|---|---|
| Legal in the US | ✗ | ✓ |
| Available globally | ✓ | ✗ |
| Settlement currency | USDC | USD |
| Custody | Self-custody or 2-of-2 multi-sig | Segregated FDIC-insured account |
| Trading fees | Low per-trade fee (added late 2025) | ~$0.01–0.07 per contract |
| Resolution | UMA optimistic oracle | Kalshi staff, CFTC-supervised |
| 1099 tax form | ✗ | ✓ |
| Mobile app | ✓ | ✓ |
| Public API | ✓ | ✓ |
| Political markets | Extensive | Approved October 2024 |
| Sports markets | Extensive | Growing |
| Economic data markets | Limited | Core category |
| Entertainment markets | Extensive | Selective |
Regulation: the headline difference
Kalshi
Kalshi is a CFTC-registered Designated Contract Market (DCM). This means it's supervised by the Commodity Futures Trading Commission — the same federal agency that regulates CME (Chicago Mercantile Exchange) and ICE (Intercontinental Exchange).
Practical implications:
- Legal in all 50 US states (federal CFTC authority preempts state gambling law)
- Customer funds held in segregated accounts at FDIC-insured banks
- Trades reported to the CFTC
- 1099 tax forms issued automatically
- Anti-money-laundering and market-surveillance obligations
Kalshi prevailed in an October 2024 Fifth Circuit ruling that allowed political event contracts. This was a landmark decision — it established that political outcomes are legitimate subjects for CFTC-regulated event contracts.
Polymarket
Polymarket is not registered with any US regulator. It settled with the CFTC in January 2022 ($1.4M penalty) and blocks US IP addresses. Outside the US, Polymarket operates in varying levels of regulatory acceptance — accessible in most of Latin America, Africa, and Asia; restricted in much of Europe.
Practical implications:
- Not legally available in the US
- No 1099 tax forms — users self-report
- No formal customer-fund regulations — safety depends on smart contract architecture
- Platform risk profile depends on your jurisdiction
See is Polymarket legal for the detailed regulatory landscape.
Bottom line: For a US user, Kalshi is the unambiguous regulatory choice. For a non-US user, both platforms have legal complexity worth understanding.
Market universe
Polymarket
Polymarket has the broader market universe:
- Politics — US, UK, Germany, France, India, Canada, Mexico, Brazil, Argentina, etc.
- Sports — NFL, NBA, MLB, NHL, Premier League, Champions League, F1, UFC, esports
- Crypto — BTC, ETH price milestones, ETF approvals, exchange hacks, protocol events
- Entertainment — Oscars, Grammys, reality TV, box office
- Science — Nobel Prize categories, SpaceX launches, AI benchmarks
- Weather and climate — major hurricanes, El Niño, temperature records
- Economics — limited coverage vs Kalshi
- Celebrity — mergers, divorces, cultural events
Polymarket will list a market on virtually anything with a defined resolution source.
Kalshi
Kalshi's market universe is narrower but deeper in specific categories:
- Economic data — Fed decisions, CPI, unemployment, GDP, jobs (Kalshi's native territory, deepest liquidity)
- Weather — temperature, hurricanes, snowfall
- Politics — presidential, Senate, House, governors, primaries, confirmations (post-October 2024)
- Sports — growing since 2024–2025 sports contract approvals
- Crypto — BTC/ETH price milestones, halvings
- Science — Nobel Prizes, FDA approvals, space launches (limited)
- Entertainment — selective
Kalshi adds new markets more conservatively than Polymarket because each new market structure requires CFTC approval. This is a trade-off: less variety, but more quality control.
Bottom line: Polymarket wins on breadth; Kalshi wins on depth in specific categories (especially economics).
Fees
Polymarket
- Trading: Per-trade fee schedule introduced in late 2025 (historically 0%); transparently shown on the trade ticket. You also pay the bid/ask spread (1–3 cents on liquid markets) and ~$0.01 in Polygon gas per trade.
- Deposit: Free to bridge USDC from another wallet. 3–5% via in-app MoonPay card onramp.
- Withdrawal: Free to your own Polygon wallet. 1–3% via Onramper fiat offramp.
Kalshi
- Trading: Per-contract fee, shown on-screen before confirming. Typically a few cents per contract. Exact amount varies by market.
- Deposit: Free via ACH. Small fee via wire. 1–2% via debit card.
- Withdrawal: Free via ACH.
For most retail traders, Kalshi's per-contract fee and Polymarket's fee + spread land in a similar range — materially below traditional sportsbook vig of 4–5%. The exact comparison depends on trade size, market liquidity, and the specific Polymarket fee tier.
Bottom line: Polymarket is cheaper for large, liquid trades. Kalshi's fees are transparent and predictable.
Custody
Polymarket
- Self-custody mode: Your USDC lives in your own wallet. Polymarket cannot touch it. You control the keys.
- Magic email mode: 2-of-2 multi-sig between you and Polymarket/Magic. Neither party can unilaterally move funds. Polymarket cannot seize; you can't withdraw if Polymarket's key infrastructure is down.
Neither mode is a traditional custodial account. Your funds are yours, provably, via the blockchain.
Kalshi
Traditional custodial account at a bank. Your USD sits in a segregated, FDIC-insured account. Kalshi cannot spend it for their own purposes, but they hold it in your name.
If Kalshi were to become insolvent, your funds are protected by FDIC insurance (up to $250k) and CFTC segregation rules. In the 2008 financial crisis, segregated customer funds at brokerages were returned without loss even in bankrupt firms.
Bottom line: Polymarket's custody model is more trust-minimized (no counterparty risk from the platform). Kalshi's is more familiar and insured by traditional institutions.
Resolution
Polymarket
Uses UMA's optimistic oracle — decentralized, on-chain, cryptoeconomically secured. Most markets resolve automatically within the 2-hour dispute window. Disputed markets escalate to a UMA token holder vote.
Strengths: trust-minimized, transparent, no single party can manipulate outcomes.
Weaknesses: ambiguous markets can have contentious disputes that take days to resolve.
Kalshi
Centralized resolution — Kalshi's staff reads the specified source at the specified time and declares the outcome. Subject to CFTC oversight and a defined dispute process.
Strengths: fast, clear, accountable.
Weaknesses: requires trusting Kalshi's judgment. No decentralized check.
Both have resolved tens of thousands of markets without major incident. Polymarket's model is more philosophically trust-minimized; Kalshi's is more practically efficient.
Bottom line: Different trust models. For routine markets, both work well.
User experience
Polymarket
Modern, crypto-native UI. Optimized for power users. Has all the standard features (order book, portfolio, watchlist, leaderboard, live charts). The onramp flow (MoonPay, wallet connection) adds friction for non-crypto users.
Mobile app is polished and full-featured.
Kalshi
Traditional brokerage-style UI. Simpler for users coming from Schwab or Robinhood. Deposits via ACH/debit are faster to onboard than Polymarket for first-time users.
Mobile app is polished and full-featured.
Bottom line: Polymarket favors crypto-comfortable users. Kalshi favors traditional-finance users. Both are well-designed.
Taxation
Polymarket
No 1099 issued. Users are responsible for tracking every trade and reporting gains. In the US, this is particularly complex because the platform is unregistered. See polytaxes.com for detailed tax coverage.
Kalshi
1099-B issued automatically for reportable gains. Tax treatment follows standard short-term capital gains / ordinary income rules.
Bottom line: For US users, Kalshi's tax simplicity is a significant advantage.
For which user is each better?
You should use Kalshi if:
- You live in the United States
- You prefer traditional finance custody and regulatory oversight
- You want automatic 1099 tax forms
- Your primary interest is economic data contracts (Fed, CPI, unemployment)
- You don't want to touch crypto
You should use Polymarket if:
- You live outside the United States
- You're comfortable with crypto (or willing to learn)
- You want the broadest market universe — entertainment, niche international, crypto-native
- You value decentralized custody and trust-minimized resolution
- You value low per-trade fees on large positions
You should use both if:
- You're outside the US and you arbitrage across platforms
- You want maximum market selection
- You're a sophisticated trader looking for cross-platform spreads
- You want exposure to events that only exist on one platform (e.g., niche international politics on Polymarket, specific economic data on Kalshi)
Common arbitrage patterns
Professional traders running both platforms look for:
- Cross-platform spreads. Same event, different prices. Happens frequently during high-volatility periods (elections, major economic releases).
- Single-platform mispricing. A market more liquid on one platform catches news faster; trade the lagging platform.
- Spread vs fee economics. Polymarket's fee plus spread vs Kalshi's small per-contract fee creates net-cost differences depending on position size.
Retail traders generally don't capture enough edge to make cross-platform arbitrage worthwhile after fees and latency. But for sophisticated traders with capital and automation, it's a real strategy.
FAQ
Frequently asked questions
Which platform has better odds?+
For the same event, prices typically differ by 1–3 cents between Polymarket and Kalshi, with one or the other leading depending on market. Neither has systematically better pricing; both converge toward fair value as volume increases.
Which platform has more users?+
Polymarket has the larger global user base. Kalshi has the larger US user base. During the 2024 US election cycle, Polymarket's volume was an order of magnitude larger than Kalshi's.
Can I arbitrage between them?+
Yes. Spreads regularly appear, especially during high-volatility periods. Execution requires accounts on both platforms, fast transaction flow, and fee/slippage awareness. Most retail traders don't capture enough edge after costs.
Does Kalshi have every market Polymarket has?+
No. Kalshi's market universe is narrower — focused on CFTC-approvable categories. Niche entertainment, international politics, and some crypto protocol markets exist only on Polymarket.
Which is safer?+
Different safety profiles. Polymarket is safer on custody (self-custody vs custodial). Kalshi is safer on regulatory (CFTC-supervised vs unregistered). For US users, Kalshi is unambiguously safer on the regulatory dimension, which usually dominates the calculus.
Can I use the same trading strategies on both?+
Mostly yes. The mechanics (YES/NO contracts, order books, resolution) are the same. Market structure (fees, liquidity, spread) differs enough that you may need to tune execution per platform.
Which platform has better API support?+
Both have functional APIs. Kalshi's REST/WebSocket API is well-documented and standardized. Polymarket's is powerful (direct on-chain and off-chain data) but requires more crypto-specific knowledge.
Do either pay interest on idle funds?+
Neither currently pays interest. Your USDC on Polymarket and your USD on Kalshi both sit at 0% yield. If interest on idle capital matters, factor that into your allocation.
Related reading
What is Polymarket? A complete beginner's guide
Polymarket is the world's largest decentralized prediction market, built on Polygon and settled in USDC. Here's how it actually works, what makes it different, and why it matters.
What is Kalshi? The first federally regulated US event-contract exchange
Kalshi is a CFTC-regulated designated contract market (DCM) that lets US residents trade event contracts on politics, economics, sports, weather, and crypto. Here's how it works and why it matters.
Is Polymarket legal? Global legality explained (2026 update)
Polymarket's legality varies widely by country. It's blocked in the US, grey-zone in much of the EU, broadly accessible across Latin America, Asia, and Africa. Here's the full landscape.
How to sign up for Polymarket: the complete step-by-step guide
Create a Polymarket account in under 10 minutes. Full walkthrough covering email signup, wallet setup, USDC funding, and your first trade.
How to sign up for Kalshi: the complete US signup guide
Sign up for Kalshi in 10 minutes. Full walkthrough: account creation, KYC, bank linking, first deposit, first trade. Kalshi is CFTC-regulated and legal in all 50 US states.