Polymarket vs Kalshi: Which Prediction Market Is More Accurate?
A data-driven comparison of prediction market accuracy between Polymarket and Kalshi, analyzing Brier scores, hit rates, and performance across different time horizons.
2042
Total Markets
0.029
Polymarket Brier
0.079
Kalshi Brier
93%
Overall Hit Rate
Key Findings
Our analysis of 2042 resolved prediction markets reveals clear patterns in accuracy between the two major platforms:
- Polymarket: 0.029 Brier score, 96% hit rate across 1055 markets
- Kalshi: 0.079 Brier score, 90% hit rate across 987 markets
What Is Brier Score?
The Brier score measures the accuracy of probabilistic predictions. It ranges from 0 to 1, where:
- 0 = Perfect prediction
- 0.25 = Random guessing on a binary outcome
- 1 = Completely wrong
Hit Rate Explained
Hit rate measures how often the market's favorite outcome (probability > 50%) actually occurred. While intuitive, it doesn't capture the full picture of prediction quality—a market predicting 51% on every outcome would have a mediocre Brier score despite potentially high hit rate.
Accuracy by Time Horizon
Markets become more accurate as they approach resolution. Here's how each platform performs at different time horizons:
| Horizon | Polymarket | Kalshi | |---------|------------|--------| | 14 days | N/A | N/A | | 10 days | N/A | N/A | | 7 days | N/A | N/A | | 2 days | N/A | N/A | | 1 day | N/A | N/A | | 12 hours | N/A | N/A |
Why the Difference?
Several factors contribute to accuracy differences between platforms:
Conclusion
Both platforms demonstrate strong predictive capabilities, with Brier scores well below the 0.25 random-guessing threshold. For individual predictions, consider checking both platforms and looking for consensus or divergence in their probabilities.
Data updated: 3/8/2026. Analysis based on 2042 resolved markets.