Kalshi vs Polymarket 2026

The Two Biggest Prediction Markets, Compared

Kalshi and Polymarket are the two dominant prediction markets for US traders in 2026. Both offer binary event contracts priced between $0 and $1. If you are new to how prediction markets work, start there. But the fee structures, liquidity profiles, market coverage, and regulatory frameworks differ enough that the same trade can be profitable on one platform and negative EV on the other.

What changed in 2026: Polymarket launched a CFTC-regulated US version with a completely different fee model (0.1% taker fee per trade instead of 2% on winnings). This changes the math for US-based traders significantly. The analysis below covers both Polymarket Global and Polymarket US where fees differ.

Where Each Platform Wins

Kalshi wins on: regulatory clarity (CFTC-regulated, 1099s, segregated accounts), exclusive market categories (economic data, weather, Fed decisions), and fee efficiency on extreme-price contracts (below 20¢ or above 80¢ where the formula-based fee rounds to near zero).

Polymarket wins on: raw fee savings across most price ranges (especially on the US platform at 0.1% per trade), liquidity depth on political and cultural markets, no position limits, multi-outcome market availability, and international access. The US version adds CFTC regulation while keeping fees well below Kalshi.

Fee Worked Examples: Three Platforms in One

The fee comparison now involves three models: Kalshi (formula per trade), Polymarket Global (2% on winnings), and Polymarket US (0.1% taker fee per trade). Here is how they play out at three representative price points.

At 20¢ (deep value contract):

• Kalshi: ceil(0.07 × 0.20 × 0.80 × 100)/100 = $0.02 per side, $0.04 round-trip
• Polymarket Global: 2% of $0.80 profit on a win = $0.016. Nothing on a loss.
• Polymarket US: 0.1% × $0.20 = $0.0002 per side, $0.0004 round-trip

Polymarket US is 100x cheaper than Kalshi at this price point. Run the exact numbers for your position size with the fee calculator.

At 50¢ (coin-flip contract):

• Kalshi: $0.02 per side, $0.04 round-trip
• Polymarket Global: 2% of $0.50 profit on a win = $0.01
• Polymarket US: 0.1% × $0.50 = $0.0005 per side, $0.001 round-trip

This is the most common price range. Polymarket US costs 40x less than Kalshi per contract.

At 80¢ (high-probability contract):

• Kalshi: $0.02 per side, $0.04 round-trip
• Polymarket Global: 2% of $0.20 profit = $0.004 on a win
• Polymarket US: 0.1% × $0.80 = $0.0008 per side, $0.0016 round-trip

At every price point, Polymarket US undercuts both Kalshi and Polymarket Global by a wide margin. The absolute dollar differences are small per contract but compound fast at volume.

Fee Crossover Point

For Kalshi vs Polymarket Global, the fee structures cross at approximately 29¢. Below that price, Kalshi's formula-based fee produces a lower per-contract cost than Polymarket Global's 2%-on-winnings model when you factor in win rates. Above 29¢, Polymarket Global is cheaper on every winning trade.

Polymarket US changes this entirely. At 0.1% per trade, Polymarket US is cheaper than Kalshi at every price point. There is no crossover. The 0.1% flat rate produces a lower fee than Kalshi's 7% × p × (1-p) formula across the entire 1¢ to 99¢ range. For US traders with access to Polymarket US, the fee decision is straightforward.

For international traders on Polymarket Global, the 29¢ crossover still applies. Use the EV calculator to model the breakeven win rate at any price point on all three fee models.

Market Coverage Comparison

The overlap between Kalshi and Polymarket is narrower than most traders expect. Both cover headline political markets - presidential elections, congressional control, major state races. Beyond that, the catalogs diverge.

Kalshi exclusives: economic indicator contracts (CPI prints, jobs reports, GDP), weather markets (hurricane landfalls, temperature records), Fed rate decisions, and government shutdown events. These categories are part of Kalshi's CFTC-approved contract specifications and do not exist on Polymarket.

Polymarket exclusives: cultural events (awards shows, viral moments), crypto-native markets (token prices, DeFi protocol events), international politics beyond US elections, and multi-outcome markets with three or more possible results. Polymarket also tends to list niche or emerging-news markets faster since it does not require CFTC approval for each new contract.

Execution Quality

Kalshi offers a full central limit order book with limit orders, market orders, and bracket orders. You can see the full depth of the order book - every bid and ask at every price level - before placing a trade. This transparency lets you estimate slippage on larger positions before committing capital.

Polymarket also operates an order book with limit and market orders, but it runs on the Polygon blockchain. Order matching happens off-chain through an operator, with settlement on-chain. Polymarket generally has deeper liquidity on its top markets, meaning tighter spreads and less slippage on five-figure positions. On mid-tier or niche markets, both platforms can have thin books where orders above 500 contracts start moving the price.

Both platforms offer API access for programmatic trading, though Kalshi's REST API is more conventional while Polymarket requires interacting with smart contract infrastructure.

Tax and Regulatory Differences

This is the sharpest divergence, and it directly affects your after-tax returns — see our prediction market tax guide for the full breakdown. Kalshi is a CFTC-regulated Designated Contract Market. It issues 1099 forms, holds customer funds in segregated accounts at regulated banks, and reports to US tax authorities. Gains and losses on Kalshi contracts are treated as Section 1256 contracts - 60% long-term, 40% short-term capital gains regardless of holding period. This is a meaningful tax advantage for active traders in higher brackets.

Polymarket Global operates offshore and does not issue 1099s. Traders are responsible for self-reporting. Funding and withdrawal involve USDC on Polygon, which creates additional crypto taxable events. There is no segregated account protection; funds sit in smart contracts with counterparty risk distinct from a regulated exchange.

Polymarket US is CFTC-regulated and issues 1099 forms. This eliminates the tax reporting gap that previously made Kalshi the clear winner for compliance-focused traders. Gains on Polymarket US contracts qualify for Section 1256 treatment (60/40 long-term/short-term split), matching Kalshi's tax structure. For the full breakdown, see our prediction market tax guide.

The Practical Decision

Most serious prediction market traders maintain accounts on both platforms and route each trade based on specific criteria:

1. Does the market exist on both? Economic data and weather are Kalshi-only. Many cultural and international markets are Polymarket-only.
2. What are the total fees at this price point? Use the fee calculator to compare exact costs.
3. Is there enough liquidity at your intended size? A 3% fee savings means nothing if you lose 4% to slippage on a thin order book.
4. If you trade 50+ contracts per month on political markets, Polymarket's fee savings compound to real money - potentially $50-100/month depending on position sizes and win rates.
5. If you need clean tax reporting and want to avoid crypto on-ramp/off-ramp events, Kalshi eliminates that overhead entirely.
6. If you need API access for systematic strategies, both platforms offer it, but evaluate documentation quality and rate limits for your specific use case.

The optimal strategy is not loyalty to a single platform. It is routing every trade to the venue with the best net economics for that specific contract.

The 2026 shift: With Polymarket US now CFTC-regulated at 0.1% fees, the calculus has changed. US traders who previously defaulted to Kalshi for regulatory clarity now have a regulated alternative with dramatically lower fees. Kalshi's edge is now primarily in exclusive market categories (economics, weather, Fed) and for traders already embedded in the Kalshi ecosystem. For political and cultural markets available on both platforms, Polymarket US is the better deal on fees and regulation.

For the full framework on how to build a systematic edge across platforms, read our prediction market strategy guide. To see how fees affect EV across all eight prediction market platforms, use the fee calculator.

Which Platforms Route Through Which Exchange

The prediction market landscape in 2026 includes front-ends that route orders to these two exchanges. Coinbase routes through Kalshi's order book. Robinhood routes through Kalshi. DraftKings routes through CME Group. This means a trade placed on Coinbase or Robinhood hits Kalshi's liquidity pool, while DraftKings taps a separate exchange entirely. When comparing Kalshi vs Polymarket liquidity, factor in that Kalshi's order book includes flow from multiple front-ends.