Home › Polymarket vs Kalshi › Price gaps
Updated September 24, 2026 at 18:24 UTC · refreshed twice a day · free CSV and JSON below
Across 216 outcomes priced on both Polymarket and Kalshi on September 24, 2026, the two exchanges differ by 1.1 points on average (median 1.0); 84% are within 2 points and 98% within 5. Among the 62 competitive outcomes (both prices between 10% and 90%) the average gap is 1.6 points. The widest: Which party wins the 2028 presidential election, Democrats (Polymarket 66.5%, Kalshi 58.5%).
| Category | Outcomes | Average gap (pts) | Median gap | Within 2 pts |
|---|---|---|---|---|
| Economy and business | 3 | 4.7 | 5.3 | 33% |
| Elections | 16 | 1.7 | 0.9 | 75% |
| Fed | 15 | 1.3 | 1.0 | 80% |
| Governor races | 66 | 1.1 | 1.0 | 86% |
| Senate races | 66 | 1.1 | 1.0 | 79% |
| Sports | 50 | 0.8 | 0.9 | 96% |
| Market | Outcome | Polymarket | Kalshi | Gap (pts) |
|---|---|---|---|---|
| Which party wins the 2028 presidential election | Democrats | 66.5% | 58.5% | +8.0 |
| Which party wins the 2028 presidential election | Republicans | 33.5% | 41.5% | -8.0 |
| US recession by the end of 2026 | Yes | 11.5% | 4.5% | +7.0 |
| Will Anthropic or OpenAI IPO first | OpenAI | 5.1% | 10.5% | -5.3 |
| South Dakota senate race | Republican (Mike Rounds) | 95.2% | 90.8% | +4.3 |
| Kansas governor race | Republican (Ty Masterson) | 73.5% | 69.5% | +4.0 |
| Nevada governor race | Republican (Joe Lombardo) | 50% | 53.5% | -3.5 |
| Fed decision in December 2026 | No change | 26.5% | 23.5% | +3.0 |
| Brazil presidential election winner | Luiz Inácio Lula da Silva | 43.5% | 46.5% | -3.0 |
| NBA champion 2027 | New York Knicks | 11.5% | 8.5% | +3.0 |
| Florida senate race | Democrat (Angie Nixon) | 8.5% | 11.5% | -3.0 |
| Texas senate race | Republican (Ken Paxton) | 39.5% | 42.5% | -3.0 |
Gap = Polymarket minus Kalshi in percentage points, before fees. Senate and governor races compare each party's candidate; Fed meetings compare the same decision outcome.
More: Polymarket vs Kalshi, event by event · Senate forecast with Kalshi prices · Fed rate odds on both · Arbitrage calculator
Across 216 outcomes priced on both Polymarket and Kalshi on September 24, 2026, the two exchanges differ by 1.1 points on average (median 1.0); 84% are within 2 points and 98% within 5. Among the 62 competitive outcomes (both prices between 10% and 90%) the average gap is 1.6 points. The widest: Which party wins the 2028 presidential election, Democrats (Polymarket 66.5%, Kalshi 58.5%).
They are separate exchanges with their own traders, fees, rules and settlement sources, and money cannot move freely between them, so the same event can trade at slightly different prices.
Only if the gap is larger than both exchanges' fees and the two contracts settle on exactly the same rules. Check with the arbitrage calculator: polymarkettrader.com/tools/polymarket-arbitrage-calculator/.
Polymarket prices are the outcome prices Polymarket publishes; Kalshi prices are the midpoint of its best bid and ask (the last trade when the book is one-sided), both read on the same run. The gap is Polymarket minus Kalshi in percentage points, before fees.
Data: CSV · JSON (CC BY 4.0, attribution: PolymarketTrader.com). Polymarket View is independent and not affiliated with Polymarket or Kalshi. Educational information, not financial advice.