GPT-5.5 Pro vs Kimi K2.6
GPT-5.5 Pro 
Kimi K2.6 Verdict
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 60.5.
- GPT-5.5 Pro (xhigh) is stronger in maths, reasoning.
- Kimi K2.6 is stronger in agents & tools, coding, composite, human preference, instruction following, knowledge, long context, multimodal.
- Kimi K2.6 is 39× cheaper ($1.71 vs $67.50 per 1M blended).
- Kimi K2.6 streams 8.9× faster (36 vs 4 tokens per second).
| Metric | GPT-5.5 Pro (xhigh) | Kimi K2.6 |
|---|---|---|
| BenchLeader Index | 67.1 | 60.5 |
| Maths score | 74.5 | 57.5 |
| Reasoning score | 80.1 | 62.5 |
| Agents & tools score | – | 47.0 |
| Coding score | – | 60.3 |
| Composite score | – | 63.8 |
| Human preference score | – | 60.7 |
| Instruction following score | – | 73.9 |
| Knowledge score | – | 58.6 |
| Long context score | – | 67.0 |
| Multimodal score | – | 63.5 |
| Blended price $/M | $67.50 | $1.71 |
| Output speed | 4 tok/s | 36 tok/s |
| Time to first answer | 3.5 s | 127.5 s |
| Context window | 1.1M | 262k |
| GPQA Diamond | – | 90.8% |
| FrontierMath Tiers 1–3 | 87.7% | 57.2% |
| FrontierMath Tier 4 | 78.0% | 25.6% |
| OTIS Mock AIME | – | 96.1% |
| SWE-bench Verified (Epoch) | – | 76.7% |
| SimpleQA Verified | – | 34.9% |
| OSWorld-Verified 2.0 | – | 4.6% |
| SciCode | – | 53.5% |
| WeirdML | – | 55.9% |
| APEX-Agents | – | 18.9% |
| ProofBench | – | 16.0% |
| Epoch Capabilities Index | – | 151 |
| LMArena Text | – | 1460 |
| LMArena Hard Prompts | – | 1485 |
| LMArena Coding | – | 1514 |
| LMArena WebDev | – | 1509 |
| LMArena Vision | – | 1280 |
| AA Intelligence Index | – | 27.5 |
| IFBench | – | 76.0% |
| AA-LCR | – | 81.0% |
| MMMU-Pro | – | 79.4% |
| AA-Omniscience | – | 5.3 |
| Terminal-Bench Hard | – | 43.9% |
| GPQA Diamond (AA) | – | 91.1% |
| Humanity's Last Exam (AA) | – | 37.5% |
| SciCode (AA) | – | 51.5% |
| τ²-Bench Telecom (AA) | – | 95.9% |
| LiveCodeBench | – | 86.8% |
| MMLU-Pro | – | 87.6% |
| LegalBench | – | 84.7% |
| CorpFin | – | 66.7% |
| TaxEval | – | 74.7% |
| Terminal-Bench 2.1 (Vals) | – | 53.6% |
| SWE-bench (Vals) | – | 76.2% |
| GPQA Diamond (Vals) | – | 89.1% |
| Vals Index | – | 43.5 |
| HiL-Bench | – | 18.7% |
| EQ-Bench 4 | – | 1202 |
| ARC-AGI-1 | 95.0% | – |
| ARC-AGI-2 | 84.2% | – |
| CritPt | 30.6% | 8.0% |
| GDPval (AA) | – | 29.8% |
| τ²-Bench Banking (AA) | – | 23.3% |
| ITBench SRE (AA) | – | 31.2% |
| APEX-Agents (AA) | – | 28.5% |
| CaseLaw v2 | – | 61.2% |
| Code Migration | – | 27.8% |
| CyberBench | – | 74.3% |
| Excel Modeling Benchmark | – | 57.9% |
| Finance Agent v2 | – | 44.9% |
| Harvey's Legal Agent Benchmark | – | 1.7% |
| Legal Research Bench | – | 15.9% |
| MedCode | – | 40.1% |
| MedScribe | – | 78.2% |
| MMMU-Pro (Vals) | – | 86.3% |
| MortgageTax | – | 65.8% |
| ProgramBench | – | 0.0% |
| Public Benefits Bench | – | 56.6% |
| SAGE | – | 50.2% |
| Terminal-Bench 2.0 (Vals) | – | 57.3% |
| Vals Multimodal Index | – | 56.4% |
| Vibe Code Bench v1.1 | – | 37.9% |
| LMArena Maths | – | 1478 |
| LMArena Creative Writing | – | 1431 |
| LMArena Instruction Following | – | 1454 |
| LMArena Multi-turn | – | 1459 |
| LMArena Longer Queries | – | 1476 |
| LMArena Document | – | 1450 |
| Chess Puzzles | – | 26.0% |
| EBR-bench | – | 2.4% |
| Mystery Game Puzzles | – | 18.0% |
| ExploitBench | – | 18.4% |
| LMCA | 53.9% | 37.3% |
| DTBench | 96.0% | 90.9% |
| CursorBench | – | 47.6% |
| GBAEval | – | 0.9% |
| ALE-Bench | – | 1092.7 |
| Vending-Bench 2 | – | 6204.6 |
| Blueprint-Bench 2 | – | 3.9% |
| GDP.pdf | – | 12.0% |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 Pro vs Kimi K2.6: questions
- Is GPT-5.5 Pro better than Kimi K2.6?
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 60.5. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 Pro (xhigh) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Which is cheaper, GPT-5.5 Pro or Kimi K2.6?
- Kimi K2.6 is cheaper: $1.71 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.5 Pro or Kimi K2.6?
- Kimi K2.6 streams faster: 36 against 4 output tokens per second.
- Which has the larger context window?
- GPT-5.5 Pro accepts more context: 1.1M against 262k tokens.