Kimi K1.5 vs Kimi K2 (0905)
Moonshot AI Kimi K1.5 | Moonshot AI Kimi K2 (0905) | |
|---|---|---|
| Overview | ||
| Company | Moonshot AI | Moonshot AI |
| Release date | Jan 20 2025 | Sep 5 2025 |
| Access | Proprietary | Open Weight |
| Specifications | ||
Parameters | — | 1T |
Context window | 128k | 256k |
| Benchmarks | ||
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | — | 65.8% |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | — | 75.1% |
| Timeline | ||
| Release gap | Kimi K1.5 shipped 228 days before Kimi K2 (0905) | |
Which is better: Kimi K1.5 or Kimi K2 (0905)?
Kimi K1.5 and Kimi K2 (0905) don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Kimi K1.5 shipped 228 days before Kimi K2 (0905), so benchmark comparisons should account for the intervening progress.
Context windows are 128k (Kimi K1.5) vs 256k (Kimi K2 (0905)). Kimi K1.5 is proprietary, while Kimi K2 (0905) is open weight.
Direct benchmark comparisons are unavailable — Kimi K1.5 and Kimi K2 (0905) don't publish scores on any of the same benchmarks.
Frequently asked questions
Kimi K1.5 was released by Moonshot AI on Jan 20 2025.
Kimi K2 (0905) was released by Moonshot AI on Sep 5 2025.
Kimi K1.5 has a 128k context window; Kimi K2 (0905) has 256k.
Kimi K1.5 is a proprietary model released by Moonshot AI. Kimi K2 (0905) is an open weight model released by Moonshot AI.