GPT-5.5 Instant vs Kimi K3
GPT-5.5 Instant 
Kimi K3 Verdict
- Kimi K3 leads on quality: 66.5 vs 60.5.
- GPT-5.5 Instant is stronger in agents & tools, instruction following, knowledge, reasoning.
- Kimi K3 is stronger in coding, composite, human preference, long context, maths, multimodal.
- Kimi K3 is 1.9× cheaper ($6.00 vs $11.25 per 1M blended).
- GPT-5.5 Instant streams 3.4× faster (129 vs 38 tokens per second).
| Metric | GPT-5.5 Instant | Kimi K3 |
|---|---|---|
| BenchLeader Index | 60.5 | 66.5 |
| Agents & tools score | 70.7 | 67.4 |
| Coding score | 61.1 | 65.0 |
| Composite score | 62.9 | 74.2 |
| Human preference score | 67.5 | 71.2 |
| Instruction following score | 69.8 | – |
| Knowledge score | 69.4 | 68.2 |
| Long context score | 61.4 | 71.1 |
| Maths score | 42.5 | 78.1 |
| Multimodal score | 59.7 | 65.0 |
| Reasoning score | 62.6 | – |
| Blended price $/M | $11.25 | $6.00 |
| Output speed | 129 tok/s | 38 tok/s |
| Time to first answer | 16.8 s | 56.3 s |
| Context window | 400k | 1.0M |
| GPQA Diamond | 82.5% | – |
| FrontierMath Tiers 1–3 | 26.3% | – |
| FrontierMath Tier 4 | 2.4% | – |
| OTIS Mock AIME | 68.1% | – |
| SciCode | 48.6% | 58.7% |
| APEX-Agents | – | 39.3% |
| FrontierCode | – | 44.2% |
| ProofBench | – | 87.0% |
| Epoch Capabilities Index | 142.5 | 157.6 |
| LMArena Text | 1474 | – |
| LMArena Hard Prompts | 1491 | – |
| LMArena Coding | 1514 | – |
| LMArena Vision | 1251 | – |
| 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 | 26.8 | 43.8 |
| IFBench | 71.5% | – |
| AA-LCR | 70.0% | 88.7% |
| MMMU-Pro | – | 80.5% |
| AA-Omniscience | 11.2 | 19.7 |
| Terminal-Bench Hard | 42.4% | – |
| GPQA Diamond (AA) | 84.7% | 93.5% |
| Humanity's Last Exam (AA) | 21.6% | 46.9% |
| SciCode (AA) | 52.5% | 59.5% |
| τ²-Bench Telecom (AA) | 49.4% | – |
| 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 |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 Instant vs Kimi K3: questions
- Is GPT-5.5 Instant better than Kimi K3?
- Kimi K3 leads on quality: 66.5 vs 60.5. The BenchLeader Index combines every independent quality benchmark; Kimi K3 is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.5 Instant better than Kimi K3 for coding?
- Kimi K3 scores higher in coding (65 vs 61 on the category index, where 50 is average).
- Is GPT-5.5 Instant better than Kimi K3 for agentic tasks?
- GPT-5.5 Instant scores higher in agentic tasks (71 vs 67 on the category index, where 50 is average).
- Which is cheaper, GPT-5.5 Instant or Kimi K3?
- Kimi K3 is cheaper: $6.00 against $11.25 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.5 Instant or Kimi K3?
- GPT-5.5 Instant streams faster: 129 against 38 output tokens per second.
- Which has the larger context window?
- Kimi K3 accepts more context: 1.0M against 400k tokens.