Kalshi vs Polymarket: how the two venues actually differ
They are not competing for the same market, they are covering different ones. Kalshi lists 9,901 open markets right now to Polymarket's 2,191 — but Polymarket turns over $74.9M in 24 hours against Kalshi's $23.5M. Far more listings on one side, far more money on the other.
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: 142 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 | 1.23¢ |
| Polymarket | 0.84¢ |
Measured across the cross-venue pairs currently on the board, not quoted from a fee schedule. Kalshi's fee scales with price, so it is highest on contracts trading near 50¢ and small at the extremes; Polymarket's cost turns up in the spread and in gas rather than as a line item.
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.
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.