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 (0.1% taker fee per trade). Then in March 2026, Polymarket Global replaced the old 2% profit fee with per-category trading fees — rates vary from 0% (geopolitical) to 1.80% peak (crypto). The analysis below covers Kalshi, Polymarket Global (new per-category model), and Polymarket US.

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: lower per-trade fees in most categories (Sports 0.75%, Politics 1.00% peak vs Kalshi's 1.75% peak), zero fees on geopolitical markets, liquidity depth on political and cultural markets, no position limits, multi-outcome market availability, and international access. The US version (0.1% flat) remains the cheapest regulated option.

Fee Worked Examples: Three Platforms in One

The fee comparison involves three models: Kalshi (formula per trade), Polymarket Global (per-category fees, March 2026+), and Polymarket US (0.1% taker fee per trade). Below we use the Politics category (feeRate=0.04, exponent=1) as representative for Polymarket Global.

At 20¢ (deep value contract):

• Kalshi taker: ceil(0.07 × 0.20 × 0.80 × 100)/100 = $0.02 per side
• Polymarket Global (Politics): 0.20 × 0.04 × (0.16)^1 = $0.00128 per side
• Polymarket US: 0.1% × $0.20 = $0.0002 per side

Polymarket Global is 15x cheaper than Kalshi taker here. Polymarket US is cheaper still.

At 50¢ (coin-flip contract):

• Kalshi taker: $0.02 per side
• Polymarket Global (Politics): 0.50 × 0.04 × 0.25 = $0.005 per side
• Polymarket US: 0.1% × $0.50 = $0.0005 per side

Polymarket Global Politics is 4x cheaper than Kalshi taker at peak. Crypto (1.80% peak) would be $0.009 — still cheaper than Kalshi's $0.02.

At 80¢ (high-probability contract):

• Kalshi taker: $0.02 per side
• Polymarket Global (Politics): 0.80 × 0.04 × 0.16 = $0.00512 per side
• Polymarket US: 0.1% × $0.80 = $0.0008 per side

Polymarket Global beats Kalshi taker at every price point for Politics, Sports, Finance, and Tech categories. For the full category fee table, see Polymarket fees explained.

Fee Crossover Point

With the new per-category model, Polymarket Global is cheaper than Kalshi taker fees for most categories at virtually every price point. The per-trade formula produces lower fees because Polymarket's category rates (0.03-0.072) are lower than Kalshi's 0.07 rate, and Polymarket uses p × feeRate × (p(1-p))^exp vs Kalshi's feeRate × p × (1-p).

The only category where Polymarket approaches Kalshi taker costs is Crypto (feeRate=0.072, very close to Kalshi's 0.07). Even there, the Polymarket formula includes an extra factor of p that makes it cheaper at all prices except exactly 50¢.

Polymarket US remains the cheapest option everywhere. At 0.1% per trade, it undercuts both Kalshi and Polymarket Global across the entire 1¢ to 99¢ range.

Geopolitical markets on Polymarket are free. If Kalshi offers the same event, Polymarket wins on fees unconditionally.

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 March 2026 shift: Polymarket Global's new per-category fees make it cheaper than Kalshi taker orders in nearly every category. Sports (0.75% peak) and Politics (1.00% peak) are roughly half of Kalshi's 1.75% peak. Geopolitical markets are free. For US traders, Polymarket US at 0.1% remains the cheapest regulated option by a wide margin. Kalshi's edge is now primarily in exclusive market categories (economic data, weather, Fed decisions) and for traders already embedded in the Kalshi ecosystem.

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.