Kalshi vs Polymarket
A live comparison of the two largest prediction markets: taker fees on a $0.50 contract, 24-hour volume on the 423 markets both list, closing-line accuracy on 5322 settled games, and the biggest disagreements between them right now.
Fees on a $0.50 contract
Kalshi 2% taker, resting sports orders free.
Polymarket 1.25% sports · 1.00% politics · 1.75% crypto.
Both scale with price × (1 − price), so fees shrink toward the extremes.
Volume, last 24h
On the 423 markets both list: Kalshi $36.6M · Polymarket $46.3M. Kalshi is sports-heavy; Polymarket carries the politics, crypto and world-event volume.
Accuracy at the close
5322 settled games: Kalshi closer 1724 · Polymarket closer 1546 · 2052 identical. Brier 0.2054 vs 0.2054. Full scoreboard.
Where the money is, by category
| Category | Matched markets | Kalshi 24h | Polymarket 24h | Kalshi share |
|---|---|---|---|---|
| the Ballon d'Or | 1 | $13.1M | $22.4M | 37% |
| Fed rate decisions | 3 | $2.2M | $8.8M | 20% |
| NBA games | 28 | $3.6M | $3.4M | 51% |
| Super Bowl futures | 1 | $4.7M | $296k | 94% |
| League of Legends matches | 4 | $1.0M | $3.3M | 24% |
| NFL games | 15 | $2.5M | $458k | 84% |
| NBA title futures | 1 | $1.7M | $1.0M | 62% |
| the next Israeli prime minister | 1 | $307k | $2.1M | 13% |
| Counter-Strike matches | 47 | $645k | $1.4M | 32% |
| MLB games | 2 | $1.6M | $145k | 92% |
| the 2028 Republican nomination | 1 | $750k | $399k | 65% |
| Champions League winner | 1 | $82k | $860k | 9% |
Biggest disagreements right now (liquid markets only)
| Market | Kalshi | Polymarket | Gap, + = Kalshi higher |
|---|---|---|---|
| Next French Presidential Election Marine Le Pen | $0.50 | $0.44 | +$0.06 |
| Pro Football: 2026 MVP Winner Justin Herbert | $0.01 | $0.06 | −$0.05 |
| Democratic Presidential Nominee 2028 Alexandria Ocasio-Cortez | $0.14 | $0.17 | −$0.04 |
| NBA: 2027 Champion Oklahoma City Thunder | $0.21 | $0.18 | +$0.03 |
| Prime Minister of Israel after the next election? Benjamin Netanyahu | $0.26 | $0.28 | −$0.02 |
| Fed Decision in December? No change | $0.24 | $0.22 | +$0.02 |
Structure
Kalshi is a CFTC-regulated exchange that settles in dollars. Polymarket settles in USDC on Polygon; check polymarket.com for what is available where you live. Neither is affiliated with this site.
How the matching works
Games are matched by league, team codes and date; multi-outcome markets outcome by outcome by name; price targets strike by strike. Anything that cannot be matched with confidence is dropped. Polymarket prices come from its live order book, Kalshi from its public API, refreshed every 45 seconds.
Questions
Which is cheaper to trade, Kalshi or Polymarket?
Both charge takers a fee proportional to price × (1 − price). At $0.50, Kalshi's fee is $0.02 per contract, 2% (rate 0.07); Polymarket's is 1.25% on sports (rate 0.05), 1.00% on politics (rate 0.04) and 1.75% on crypto (rate 0.07). Resting orders on Kalshi sports markets pay no fee.
Which has more liquidity?
On the 423 markets both venues list right now, 24-hour volume is $36.6M on Kalshi and $46.3M on Polymarket. It varies by category; the table on this page is recomputed every 45 seconds.
Which is more accurate?
On 5322 settled games, the closing price was closer to the result on Kalshi 1724 times (32%), on Polymarket 1546 (29%), and identical on 2052. Mean Brier 0.2054 vs 0.2054: at the close they are effectively equal.
Can you arbitrage between Kalshi and Polymarket?
Sometimes, briefly. When the sum of the two venues’ asks on opposite outcomes is below $1 after fees, buying both locks in the difference. The live screener shows the fee-adjusted edge on every matched market; it ignores slippage, withdrawal costs and the time it takes to move money between two accounts.