Claude Opus 4.5 vs Kimi K2.5
Claude Opus 4.5 (2025) and Kimi K2.5 (2026) compare a standalone API model against a coding-specialized model. Claude Opus 4.5 ships a 200k-token context window, while Kimi K2.5 ships a 256k-token context window. On MMLU PRO, Claude Opus 4.5 leads by 1.8 pts. On pricing, Kimi K2.5 costs $0.44/1M input tokens versus $5/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Claude Opus 4.5 is standalone API model, while Kimi K2.5 is coding-specialized model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Claude Opus 4.5 | Kimi K2.5 |
|---|---|---|
| Product type | Standalone API model | Coding-specialized model |
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | custom coding agents, code generation, and tool loops |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 200k | 256k |
| Cheapest output | $25/1M tokens | $2/1M tokens |
| Provider routes | 6 tracked | 11 tracked |
| Shared benchmarks | MMLU PRO leader | 3 rows |
Decision tradeoffs
- Claude Opus 4.5 leads the largest shared benchmark signal on MMLU PRO by 1.8 points.
- Claude Opus 4.5 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Claude Opus 4.5 for Coding, RAG, and Agents.
- Kimi K2.5 leads the largest shared benchmark signal on Google-Proof Q&A by 0.9 points.
- Kimi K2.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Kimi K2.5 has the lower cheapest tracked output price at $2/1M tokens.
- Kimi K2.5 has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Kimi K2.5 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Opus 4.5
$10,250
Cheapest tracked route/tier: Microsoft Foundry
Kimi K2.5
$852
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $9,398. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter, AWS Bedrock, and Microsoft Foundry; start route-level A/B tests there.
- Kimi K2.5 is $23/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Provider overlap exists on Microsoft Foundry, AWS Bedrock, and OpenRouter; start route-level A/B tests there.
- Claude Opus 4.5 is $23/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Opus 4.5 adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-11-01 | 2026-03-15 |
| Context window | 200k | 256k |
| Parameters | — | 1T (MoE, 384 experts) |
| Architecture | decoder only | mixture of experts |
| License | Proprietary | MIT |
| Knowledge cutoff | 2025-12 | - |
Pricing and availability
| Pricing attribute | Claude Opus 4.5 | Kimi K2.5 |
|---|---|---|
| Input price | $5/1M tokens | $0.44/1M tokens |
| Output price | $25/1M tokens | $2/1M tokens |
| Providers |
Capabilities
| Capability | Claude Opus 4.5 | Kimi K2.5 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Claude Opus 4.5 | Kimi K2.5 |
|---|---|---|
| MMLU PRO | 88.9 | 87.1 |
| Google-Proof Q&A | 87.0 | 87.9 |
| BFCL | 77.5 | 47.1 |
Deep dive
On shared benchmark coverage, MMLU PRO has Claude Opus 4.5 at 88.9 and Kimi K2.5 at 87.1, with Claude Opus 4.5 ahead by 1.8 points; Google-Proof Q&A has Claude Opus 4.5 at 87 and Kimi K2.5 at 87.9, with Kimi K2.5 ahead by 0.9 points; BFCL has Claude Opus 4.5 at 77.5 and Kimi K2.5 at 47.1, with Claude Opus 4.5 ahead by 30.4 points. The largest visible gap is 30.4 points on BFCL, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on vision: Claude Opus 4.5, multimodal input: Claude Opus 4.5, reasoning mode: Claude Opus 4.5, tool use: Claude Opus 4.5, and code execution: Claude Opus 4.5. Both models share function calling 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 on the cheapest tracked provider, while Kimi K2.5 lists $0.44/1M input and $2/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Kimi K2.5 lower by about $10.09 per million blended tokens. Availability is 6 providers versus 11, so concentration risk also matters.
Choose Claude Opus 4.5 when coding workflow support are central to the workload. Choose Kimi K2.5 when coding workflow support, 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.
FAQ
Which has a larger context window, Claude Opus 4.5 or Kimi K2.5?
Kimi K2.5 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 K2.5?
Kimi K2.5 is cheaper on tracked token pricing. Claude Opus 4.5 costs $5/1M input and $25/1M output tokens. Kimi K2.5 costs $0.44/1M input and $2/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Opus 4.5 or Kimi K2.5 open source?
Claude Opus 4.5 is listed under Proprietary. Kimi K2.5 is listed under MIT. 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 K2.5?
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 K2.5?
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 K2.5?
Claude Opus 4.5 is available on Microsoft Foundry, Anthropic, GCP Vertex AI, AWS Bedrock, and OpenRouter. Kimi K2.5 is available on Cloudflare Workers AI, Fireworks AI, OpenRouter, Together AI, and Fireworks AI. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.