Claude Opus 4.5 vs Kimi K2 Thinking
Claude Opus 4.5 (2025) and Kimi K2 Thinking (2025) are frontier-tier reasoning models from Anthropic and Moonshot AI. Claude Opus 4.5 ships a 200K-token context window, while Kimi K2 Thinking ships a 256K-token context window. On pricing, Kimi K2 Thinking costs $0.6/1M input tokens versus $5/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Kimi K2 Thinking is ~733% cheaper at $0.6/1M; pay for Claude Opus 4.5 only for coding workflow support.
Specs
| Released | 2025-11-01 | 2025-01-01 |
| Context window | 200K | 256K |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-12 | - |
Pricing and availability
| Claude Opus 4.5 | Kimi K2 Thinking | |
|---|---|---|
| Input price | $5/1M tokens | $0.6/1M tokens |
| Output price | $25/1M tokens | $2.5/1M tokens |
| Providers |
Capabilities
| Claude Opus 4.5 | Kimi K2 Thinking | |
|---|---|---|
| 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 vision: Claude Opus 4.5, multimodal input: Claude Opus 4.5, function calling: Claude Opus 4.5, tool use: Claude Opus 4.5, and code execution: Claude Opus 4.5. Both models share reasoning mode and 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, Claude Opus 4.5 lists $5/1M input and $25/1M output tokens, while Kimi K2 Thinking lists $0.6/1M input and $2.5/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Kimi K2 Thinking lower by about $9.83 per million blended tokens. Availability is 6 providers versus 5, so concentration risk also matters.
Choose Claude Opus 4.5 when coding workflow support and broader provider choice are central to the workload. Choose Kimi K2 Thinking when long-context analysis, larger context windows, and lower input-token cost 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.
FAQ
Which has a larger context window, Claude Opus 4.5 or Kimi K2 Thinking?
Kimi K2 Thinking supports 256K tokens, while Claude Opus 4.5 supports 200K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Claude Opus 4.5 or Kimi K2 Thinking?
Kimi K2 Thinking is cheaper on tracked token pricing. Claude Opus 4.5 costs $5/1M input and $25/1M output tokens. Kimi K2 Thinking costs $0.6/1M input and $2.5/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Opus 4.5 or Kimi K2 Thinking open source?
Claude Opus 4.5 is listed under Proprietary. Kimi K2 Thinking is listed under Proprietary. 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 vision, Claude Opus 4.5 or Kimi K2 Thinking?
Claude Opus 4.5 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Claude Opus 4.5 or Kimi K2 Thinking?
Claude Opus 4.5 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Claude Opus 4.5 and Kimi K2 Thinking?
Claude Opus 4.5 is available on Microsoft Foundry, Anthropic, GCP Vertex AI, AWS Bedrock, and OpenRouter. Kimi K2 Thinking is available on Fireworks AI, GCP Vertex AI, NVIDIA NIM, AWS Bedrock, and OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-04-27. Data sourced from public model cards and provider documentation.