Polymarket vs Kalshi: fees, markets, liquidity and odds compared
They are not competing for the same market, they are covering different ones. Kalshi lists 9,070 open markets right now to Polymarket's 2,217 — but Polymarket turns over $242.5M in 24 hours against Kalshi's $16.4M. Far more listings on one side, far more money on the other.
Polymarket vs Kalshi at a glance
| Kalshi | Polymarket | |
|---|---|---|
| Regulation | CFTC-regulated US exchange | International exchange settled on-chain; a separate CFTC-regulated exchange serves US users |
| Money | US dollars | USDC stablecoin on the international exchange |
| Taker fee | 0.07 × contracts × P × (1 − P) | 3–5% rate on the same curve where enabled; part of the book is fee-free |
| Maker fee | Free on most series | Free, with a rebate |
| Open markets now | 9,070 | 2,217 |
| 24h volume now | $16.4M | $242.5M |
| Resolution | Rulebook per series | Oracle with a dispute window |
| Developer API | REST and WebSocket | REST, WebSocket and on-chain data |
Coverage: mostly different questions
The two venues overlap far less than people assume. Most Kalshi listings are economic indicators, weather and a long tail of recurring contracts; Polymarket's volume concentrates in a smaller number of politics, crypto and sports markets. That is why a cross-venue price comparison only applies to a slice of either board: 128 events are currently priced on both. Finding that slice reliably is the hard part. The arbitrage guide shows what the overlap is priced at today.
Fees: the number that decides most comparisons
| Venue | Average fee per contract, live board |
|---|---|
| Kalshi | 1.29¢ |
| Polymarket | 0.74¢ |
Measured across the cross-venue pairs currently on the board, not quoted from a fee schedule. Both venues charge takers on a price × (1 − price) curve: Kalshi at 7%, Polymarket at 3–5% by category where fees are enabled, with part of its book fee-free. The full formula, a fee table and a calculator are in Kalshi fees explained.
The practical differences
- Access. Kalshi is a CFTC-regulated US exchange and takes dollars directly. Polymarket settles on-chain in USDC. Which of those you can use is usually decided by where you live, not by which you prefer.
- Resolution. Kalshi publishes a rulebook per series; Polymarket resolves through an oracle with a dispute window. Two markets on the same event can still resolve differently, which is the single most expensive thing to get wrong when comparing prices across them.
- Liquidity shape. Polymarket's depth concentrates in fewer markets. Kalshi's is spread thinner across many more. A price on a thin market is a price you may not be able to trade at size.
Common questions
Is Polymarket or Kalshi better?
It depends on what you trade. Kalshi lists far more markets, especially economics, weather and recurring contracts, and takes dollars directly. Polymarket concentrates more money in fewer politics, crypto and sports markets, so those books are often deeper there, and its fees are lower where they apply at all.
Which has lower fees?
Usually Polymarket: its taker rate is 3–5% on the same curve where Kalshi's is 7%, and some Polymarket markets charge no fee. On 100 contracts at 50¢, Kalshi charges $1.75 and Polymarket $0 to $1.25. The spread you cross can matter more than either fee on a thin market.
Do Kalshi and Polymarket show the same odds?
Mostly within a few cents on events listed on both, but not always, and a gap is not automatically an arbitrage: the two contracts can settle on different terms. We measure how often they agree in do Kalshi and Polymarket odds agree.
Can I use both?
Many traders do, to get the better price on the same event. Which venues you can open an account with depends on where you live, and that changes, so check each venue's current terms.
Where these numbers come from
Both boards are ingested every few minutes and counted directly — the figures above are computed when this page is served, not written by hand. The same data is on the scanner and in the public API.
Nothing here is advice about where to trade, and availability differs by jurisdiction.