Claude Sonnet 4.6 vs Kimi K2.5
Claude Sonnet 4.6 (2026) and Kimi K2.5 (2026) compare a standalone API model against a coding-specialized model. Claude Sonnet 4.6 ships a 1m-token context window, while Kimi K2.5 ships a 256k-token context window. On MMLU PRO, Claude Sonnet 4.6 leads by 0.2 pts. On pricing, Kimi K2.5 costs $0.44/1M input tokens versus $3/1M 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 Sonnet 4.6 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 Sonnet 4.6 | 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 | 1m | 256k |
| Cheapest output | $15/1M tokens | $2/1M tokens |
| Provider routes | 6 tracked | 10 tracked |
| Shared benchmarks | MMLU PRO leader | 13 shared |
Decision tradeoffs
- Claude Sonnet 4.6 holds a shared-benchmark lead on MMLU PRO, ahead by 0.2 points.
- Claude Sonnet 4.6 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Claude Sonnet 4.6 uniquely exposes Reasoning, Code execution, and Computer use in local model data.
- Local decision data tags Claude Sonnet 4.6 for Coding, RAG, and Agents.
- Kimi K2.5 holds a shared-benchmark lead on AIME 2025, ahead by 2.1 points.
- 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 route 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 Sonnet 4.6
$6,150
Cheapest tracked route/tier: OpenRouter
Kimi K2.5
$852
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $5,298. 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 $13/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning, Code execution, and Computer use before moving production traffic.
- Provider overlap exists on OpenRouter, AWS Bedrock, and Microsoft Foundry; start route-level A/B tests there.
- Claude Sonnet 4.6 is $13/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Sonnet 4.6 adds Reasoning, Code execution, and Computer use in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-17 | 2026-03-15 |
| Context window | 1m | 256k |
| Parameters | — | 1T (MoE, 384 experts) |
| Architecture | Decoder Only | Mixture of Experts |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2025-08 | - |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.6 | Kimi K2.5 |
|---|---|---|
| Input price | $3/1M tokens | $0.44/1M tokens |
| Output price | $15/1M tokens | $2/1M tokens |
| Providers |
Capabilities
| Capability | Claude Sonnet 4.6 | Kimi K2.5 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| JSON / Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | Yes | No |
| Parallel agents | Yes | No |
Benchmarks
| Benchmark | Claude Sonnet 4.6 | Kimi K2.5 |
|---|---|---|
| MMLU PRO | 87.3 | 87.1 |
| SWE-bench Verified | 79.6 | 76.8 |
| Google-Proof Q&A | 89.9 | 87.9 |
| AIME 2025 | 94.0 | 96.1 |
| LiveCodeBench | 80.0 | 85.0 |
| Humanity's Last Exam | 33.2 | 50.2 |
| MCP-Atlas | 61.3 | 29.5 |
| CursorBench | 49.0 | 31.9 |
| τ-bench | 87.5 | 74.2 |
| Terminal-Bench 2.0 | 59.1 | 50.8 |
| MultiChallenge | 57.1 | 61.4 |
| MMMU Pro | 75.6 | 78.5 |
| SWE-rebench | 60.7 | 58.5 |
Continue comparing
Popular comparisons for Claude Sonnet 4.6
Popular comparisons for Kimi K2.5
Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.