Claude Opus 4.8 vs Kimi K3 Fast
Kimi K3 Fast is cheaper on output tokens, while Kimi K3 Fast offers a larger context window. Choose Claude Opus 4.8 or Kimi K3 Fast based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Claude Opus 4.8 | Kimi K3 Fast |
|---|---|---|
| Provider | Anthropic | Neuralwatt |
| Input / 1M tokens | $5.00 | $3.00 |
| Output / 1M tokens | $25.00 | $15.00 |
| Context window | 1M | 1M |
| Parameters | — | — |
| Open weights | — | Yes |
| Released | — | Jul 2026 |
| LMArena (Chatbot Arena) Elo score | 1461 | — |
| GPQA Diamond score | 91.0 | — |
| FrontierMath score | 47.2 | — |
| Epoch Capabilities Index score | 159 | — |
| LMArena WebDev Elo score | 1556 | — |
| LMArena Vision Elo score | 1294 | — |
FAQ
Is Claude Opus 4.8 or Kimi K3 Fast cheaper?
Kimi K3 Fast is cheaper on output tokens ($15.00 vs $25.00 per 1M).
Which has the larger context window, Claude Opus 4.8 or Kimi K3 Fast?
Kimi K3 Fast has the larger context window (1M tokens).
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.