Polymarket vs. Kalshi
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See where the two biggest prediction markets disagree. Pick any two markets, or start from the biggest gaps below: prices, volume, history and the resolution rules, side by side.
Will there be at least 10000 measles cases in the U.S. in 2026?
Vol $296 today · $6.5M total
Will there be an at least 8.0 magnitude earthquake in Japan before 2030?
Vol $1 today · $46.1K total
Kalshi is 28 points higher than Polymarket (34% vs 6%). Polymarket trades about 279.4× more volume today, so its price has more money behind it. They resolve on different dates (Jan 1 vs Jan 1), so they may not be exactly the same bet.
History starts when we first saw each market, so a newly added market has a short line.
| Polymarket | Kalshi | |
|---|---|---|
| Probability (Yes) | 6% | 34% |
| Change (24h) | +0.2 pt | +1.0 pt |
| Volume today | $296 | $1 |
| Total volume | $6.5M | $46.1K |
| Liquidity | $4.8K | — |
| Open interest | — | $13.5K |
| Resolves | 58d | 38mo |
| Tracked for | 38 hours | 25 days |
Resolution rules: read both before trusting a gap
Polymarket
This market will resolve to "Yes" if there have been the specified amount or more confirmed cases of Measles (Rubeola) in humans in the territory of the United States of America in 2026 according to the CDC case counter between January 1, 2026, 12:00 AM ET and December 31, 2026, 11:59 PM ET. Otherwise, this market will resolve to "No". The resolution source for this market will be the CDC Measles (Rubeola) counter (see: https://www.cdc.gov/measles/data-research/index.html) at the resolution time. If the counter becomes unavailable, another credible source will be used. Note: Only cases reported by the CDC Measles (Rubeola) counter will qualify, regardless of reports from U.S. State agencies or other sources.
Kalshi
If there is at least an earthquake of 8.0 magnitude with an epicenter in Japan or its territorial waters before Jan 1, 2030, then the market resolves to Yes.
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Informational only — not financial advice. Odds are mirrored from each platform and may lag the live order book.