Polymarket vs Kalshi: fees, access & the price gaps between them
Polymarket and Kalshi are the two largest prediction markets — one an offshore crypto order book, the other a CFTC-regulated US exchange. They list many of the same events at different prices, and that difference is where cross-venue arbitrage lives.
| Polymarket | Kalshi | |
|---|---|---|
| Regulation | Offshore; restricts US persons | CFTC-regulated US exchange |
| Who can trade | Most non-US jurisdictions | US residents (and some intl.) |
| Settlement | USDC on Polygon (crypto) | US dollars (bank/debit) |
| Trading fees | No trading fee (gas/spread costs) | Taker fee ≈ 7¢ × P×(1−P) per contract |
| Market breadth | Politics, crypto, sports, culture — widest | Politics, econ data, weather, sports |
| Order books | Public CLOB, deep on majors | Public book, deep on flagship events |
Why the same event trades at different prices
The two venues can't share liquidity: different countries, different money (USDC vs USD), different users. A political headline can move Polymarket's crypto-native crowd minutes before Kalshi's US retail follows — or the reverse. With no common market maker forcing convergence, gaps of 1–5 cents on the same question are routine.
The gap is the opportunity
When Polymarket prices YES at $0.47 and Kalshi prices NO at $0.505 for the same event, buying both costs $0.975 against a certain $1.00 payout — a 2.5% edge whichever way the event resolves, if both markets resolve on the same rules. Note the jurisdiction catch: a single US person generally can't hold both legs; the pairs most usable from one account are Kalshi+PredictIt (US) or Polymarket+Smarkets (non-US).
Which should you use?
For most people the answer is "whichever you're allowed to use" — regulation decides before preference does. For arbitrage specifically, the interesting question isn't which venue is better; it's where they disagree today. That changes every hour.
See the live gaps
PROVISUM scans Polymarket, Kalshi, PredictIt, Smarkets and Limitless every 10 minutes and surfaces the cross-venue hedges that are actually on the board right now — fee-adjusted, depth-checkable, honestly labeled.
Keep reading: Prediction market arbitrage: the complete guide · Polymarket arbitrage: finding mispriced markets