GPT-5.5 Pro vs Kimi K3
GPT-5.5 Pro 
Kimi K3 Verdict
- GPT-5.5 Pro (xhigh) and Kimi K3 (max) are level on quality (67.1 vs 67.2).
- GPT-5.5 Pro (xhigh) is stronger in maths, reasoning.
- Kimi K3 (max) is stronger in agents & tools, coding, composite, human preference, knowledge, long context, multimodal.
- Kimi K3 (max) is 11× cheaper ($6.00 vs $67.50 per 1M blended).
- Kimi K3 (max) streams 9.2× faster (37 vs 4 tokens per second).
| Metric | GPT-5.5 Pro (xhigh) | Kimi K3 (max) |
|---|---|---|
| BenchLeader Index | 67.1 | 67.2 |
| Maths score | 74.5 | 65.4 |
| Reasoning score | 80.1 | 68.6 |
| Agents & tools score | – | 67.5 |
| Coding score | – | 67.0 |
| Composite score | – | 84.5 |
| Human preference score | – | 68.8 |
| Knowledge score | – | 64.5 |
| Long context score | – | 71.0 |
| Multimodal score | – | 65.1 |
| Blended price $/M | $67.50 | $6.00 |
| Output speed | 4 tok/s | 37 tok/s |
| Time to first answer | 3.5 s | 58.3 s |
| Context window | 1.1M | 1.0M |
| GPQA Diamond | – | 93.1% |
| FrontierMath Tiers 1–3 | 87.7% | 72.2% |
| FrontierMath Tier 4 | 78.0% | 39.0% |
| OTIS Mock AIME | – | 97.2% |
| SimpleQA Verified | – | 50.6% |
| SimpleBench | – | 60.7% |
| SciCode | – | 58.7% |
| WeirdML | – | 82.6% |
| LMArena Text | – | 1485 |
| LMArena Hard Prompts | – | 1514 |
| LMArena Coding | – | 1538 |
| LMArena WebDev | – | 1674 |
| LMArena Agent | – | 6.2 |
| 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% |
| LiveCodeBench | – | 87.2% |
| MMLU-Pro | – | 88.0% |
| IOI | – | 48.9% |
| MCP Atlas | – | 82.3% |
| ARC-AGI-1 | 95.0% | 94.5% |
| ARC-AGI-2 | 84.2% | 60.4% |
| CritPt | 30.6% | 23.4% |
| GDPval (AA) | – | 52.4% |
| τ²-Bench Banking (AA) | – | 46.0% |
| ITBench SRE (AA) | – | 47.7% |
| Analyst Agent (AA) | – | 38.8% |
| APEX-Agents (AA) | – | 41.3% |
| BioMysteryBench | – | 71.5% |
| Code Migration | – | 16.1% |
| Excel Modeling Benchmark | – | 66.4% |
| Tax Agent Bench | – | 68.7% |
| Terminal-Bench 4.0 (Vals) | – | 12.6% |
| Terminal-Bench Science | – | 2.9% |
| Time Horizon Index: KSP | – | 10.5% |
| Vibe Code Bench 1-100 | – | 18.2% |
| FORTRESS | – | 26.6% |
| LMArena Maths | – | 1501 |
| LMArena Creative Writing | – | 1458 |
| LMArena Instruction Following | – | 1484 |
| LMArena Multi-turn | – | 1496 |
| LMArena Longer Queries | – | 1500 |
| Chess Puzzles | – | 39.0% |
| Mystery Game Puzzles | – | 26.0% |
| Surface Evolver Bench | – | 93.0% |
| DeepSWE | – | 68.5% |
| LMCA | 53.9% | 52.7% |
| DTBench | 96.0% | 91.2% |
| CursorBench | – | 60.8% |
| ALE-Bench | – | 1524.5 |
| GDP.pdf | – | 19.0% |
| FrontierSWE | – | 25.9% |
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 K3: questions
- Is GPT-5.5 Pro better than Kimi K3?
- GPT-5.5 Pro (xhigh) and Kimi K3 (max) are level on quality (67.1 vs 67.2). The BenchLeader Index combines every independent quality benchmark; Kimi K3 (max) 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 K3?
- Kimi K3 is cheaper: $6.00 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.5 Pro or Kimi K3?
- Kimi K3 streams faster: 37 against 4 output tokens per second.
- Which has the larger context window?
- GPT-5.5 Pro accepts more context: 1.1M against 1.0M tokens.