Kimi K2 Instruct vs Llama 3.1 405B Instruct
Kimi K2 Instruct (2025) and Llama 3.1 405B Instruct (2024) are frontier reasoning models from Moonshot AI and AI at Meta. Kimi K2 Instruct ships a not-yet-sourced context window, while Llama 3.1 405B Instruct ships a 128K-token context window. On pricing, Kimi K2 Instruct costs $0.6/1M input tokens versus $2.4/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Kimi K2 Instruct is ~300% cheaper at $0.6/1M; pay for Llama 3.1 405B Instruct only for provider fit.
Specs
| Released | 2025-01-01 | 2024-07-23 |
| Context window | — | 128K |
| Parameters | — | 405B |
| Architecture | decoder only | decoder only |
| License | MIT | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Kimi K2 Instruct | Llama 3.1 405B Instruct | |
|---|---|---|
| Input price | $0.6/1M tokens | $2.4/1M tokens |
| Output price | $2.5/1M tokens | $2.4/1M tokens |
| Providers |
Capabilities
| Kimi K2 Instruct | Llama 3.1 405B Instruct | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: Kimi K2 Instruct. Both models share structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Kimi K2 Instruct lists $0.6/1M input and $2.5/1M output tokens, while Llama 3.1 405B Instruct lists $2.4/1M input and $2.4/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Kimi K2 Instruct lower by about $1.23 per million blended tokens. Availability is 3 providers versus 11, so concentration risk also matters.
Choose Kimi K2 Instruct when reasoning depth and lower input-token cost are central to the workload. Choose Llama 3.1 405B Instruct when provider fit and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which is cheaper, Kimi K2 Instruct or Llama 3.1 405B Instruct?
Kimi K2 Instruct is cheaper on tracked token pricing. Kimi K2 Instruct costs $0.6/1M input and $2.5/1M output tokens. Llama 3.1 405B Instruct costs $2.4/1M input and $2.4/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Kimi K2 Instruct or Llama 3.1 405B Instruct open source?
Kimi K2 Instruct is listed under MIT. Llama 3.1 405B Instruct is listed under Open Source. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for reasoning mode, Kimi K2 Instruct or Llama 3.1 405B Instruct?
Kimi K2 Instruct has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for structured outputs, Kimi K2 Instruct or Llama 3.1 405B Instruct?
Both Kimi K2 Instruct and Llama 3.1 405B Instruct expose structured outputs. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Kimi K2 Instruct and Llama 3.1 405B Instruct?
Kimi K2 Instruct is available on Fireworks AI, Together AI, and NVIDIA NIM. Llama 3.1 405B Instruct is available on OctoAI API, Together AI, Fireworks AI, IBM watsonx, and Scale AI GenAI Platform. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Kimi K2 Instruct over Llama 3.1 405B Instruct?
Kimi K2 Instruct is ~300% cheaper at $0.6/1M; pay for Llama 3.1 405B Instruct only for provider fit. If your workload also depends on reasoning depth, start with Kimi K2 Instruct; if it depends on provider fit, run the same evaluation with Llama 3.1 405B Instruct.
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Last reviewed: 2026-04-27. Data sourced from public model cards and provider documentation.