Claude Sonnet 4.5 vs Kimi K3
Claude Sonnet 4.5 
Kimi K3 Verdict
- Kimi K3 leads on quality: 65.7 vs 57.9.
- Claude Sonnet 4.5 (high) is stronger in reasoning.
- Kimi K3 is stronger in coding, human preference, agents & tools, composite, knowledge, long context, maths, multimodal.
- They cost about the same ($6.00 per 1M blended).
| Metric | Claude Sonnet 4.5 (high) | Kimi K3 |
|---|---|---|
| BenchLeader Index | 57.9 | 65.7 |
| Coding score | 56.4 | 65.0 |
| Human preference score | 65.3 | 71.2 |
| Reasoning score | 66.4 | – |
| Agents & tools score | – | 67.4 |
| Composite score | – | 70.6 |
| Knowledge score | – | 66.8 |
| Long context score | – | 69.2 |
| Maths score | – | 78.1 |
| Multimodal score | – | 64.0 |
| Blended price $/M | $6.00 | $6.00 |
| Output speed | 40 tok/s | 37 tok/s |
| Time to first answer | 1.2 s | 57.9 s |
| Context window | 1M | 1.0M |
| SciCode | – | 58.7% |
| APEX-Agents | – | 39.3% |
| FrontierCode | – | 44.2% |
| ProofBench | – | 87.0% |
| Epoch Capabilities Index | – | 157.6 |
| LMArena Text | 1456 | – |
| LMArena Hard Prompts | 1487 | – |
| LMArena Coding | 1520 | – |
| LMArena WebDev | 1393 | – |
| LiveBench | – | 79.2% |
| LiveBench Reasoning | – | 90.7% |
| LiveBench Coding | – | 81.5% |
| LiveBench Agentic Coding | – | 62.2% |
| LiveBench Mathematics | – | 84.4% |
| LiveBench Data Analysis | – | 78.7% |
| LiveBench Language | – | 85.5% |
| AA Intelligence Index | – | 43.8 |
| AA-LCR | – | 88.7% |
| MMMU-Pro | – | 80.5% |
| AA-Omniscience | – | 19.7 |
| GPQA Diamond (AA) | – | 93.5% |
| Humanity's Last Exam (AA) | – | 46.9% |
| SciCode (AA) | – | 59.5% |
| LegalBench | – | 86.0% |
| CorpFin | – | 71.6% |
| TaxEval | – | 75.7% |
| Terminal-Bench 2.1 (Vals) | – | 80.9% |
| SWE-bench (Vals) | – | 93.4% |
| GPQA Diamond (Vals) | – | 92.9% |
| Vals Index | – | 57.8 |
| EQ-Bench 4 | – | 1339 |
| SWE-bench Verified (bash only) | 71.4% | – |
Data as of 2026-09-13. Best configuration of each model; every score links to its source on the model pages.
Claude Sonnet 4.5 vs Kimi K3: questions
- Is Claude Sonnet 4.5 better than Kimi K3?
- Kimi K3 leads on quality: 65.7 vs 57.9. The BenchLeader Index combines every independent quality benchmark; Kimi K3 is ahead overall as of 2026-09-13, but check the category scores for your use.
- Is Claude Sonnet 4.5 better than Kimi K3 for coding?
- Kimi K3 scores higher in coding (65 vs 56 on the category index, where 50 is average).
- Which is cheaper, Claude Sonnet 4.5 or Kimi K3?
- Claude Sonnet 4.5 is cheaper: $6.00 against $6.00 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Sonnet 4.5 or Kimi K3?
- Claude Sonnet 4.5 streams faster: 40 against 37 output tokens per second.
- Which has the larger context window?
- Kimi K3 accepts more context: 1.0M against 1M tokens.