Claude Opus 4.6 vs GPT-5.5 Instant
Claude Opus 4.6 
GPT-5.5 Instant Verdict
- Claude Opus 4.6 leads on quality: 63.3 vs 60.5.
- Claude Opus 4.6 is stronger in coding, composite, knowledge, long context, maths, multimodal.
- GPT-5.5 Instant is stronger in agents & tools, human preference, instruction following.
- They cost about the same ($10.00 per 1M blended).
- GPT-5.5 Instant streams 3.5× faster (129 vs 36 tokens per second).
| Metric | Claude Opus 4.6 | GPT-5.5 Instant |
|---|---|---|
| BenchLeader Index | 63.3 | 60.5 |
| Agents & tools score | 68.8 | 70.7 |
| Coding score | 62.4 | 61.1 |
| Composite score | 69.4 | 62.9 |
| Human preference score | 64.9 | 67.5 |
| Instruction following score | 53.9 | 69.8 |
| Knowledge score | 70.6 | 69.4 |
| Long context score | 65.5 | 61.4 |
| Maths score | 65.7 | 42.5 |
| Multimodal score | 63.6 | 59.7 |
| Reasoning score | 62.6 | 62.6 |
| Blended price $/M | $10.00 | $11.25 |
| Output speed | 36 tok/s | 129 tok/s |
| Time to first answer | 2.4 s | 16.8 s |
| Context window | 1M | 400k |
| GPQA Diamond | 90.5% | 82.5% |
| FrontierMath Tiers 1–3 | – | 26.3% |
| FrontierMath Tier 4 | – | 2.4% |
| OTIS Mock AIME | 94.4% | 68.1% |
| SWE-bench Verified (Epoch) | 78.7% | – |
| Humanity's Last Exam | 19.0% | – |
| Terminal-Bench | 79.8% | – |
| SimpleBench | 67.6% | – |
| SciCode | – | 48.6% |
| Cybench | 93.0% | – |
| Remote Labor Index | 4.2% | – |
| WeirdML | 77.9% | – |
| APEX-Agents | 32.4% | – |
| FrontierCode | 26.6% | – |
| GSO-Bench | 33.3% | – |
| Epoch Capabilities Index | 155.3 | 142.5 |
| LMArena Text | 1498 | 1474 |
| LMArena Hard Prompts | 1527 | 1491 |
| LMArena Coding | 1546 | 1514 |
| LMArena WebDev | 1537 | – |
| LMArena Vision | 1311 | 1251 |
| AA Intelligence Index | 31.9 | 26.8 |
| IFBench | 53.1% | 71.5% |
| AA-LCR | 78.0% | 70.0% |
| MMMU-Pro | 75.4% | – |
| AA-Omniscience | 13.7 | 11.2 |
| Terminal-Bench Hard | 48.5% | 42.4% |
| GPQA Diamond (AA) | 89.6% | 84.7% |
| Humanity's Last Exam (AA) | 39.9% | 21.6% |
| SciCode (AA) | – | 52.5% |
| τ²-Bench Telecom (AA) | 92.1% | 49.4% |
| HiL-Bench | 38.3% | – |
| EQ-Bench 4 | 1223 | – |
| Kagi LLM Benchmark | 72.4% | – |
| SWE-bench Verified (bash only) | 75.6% | – |
| SWE-bench Verified (any scaffold) | 75.6% | – |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 4.6 vs GPT-5.5 Instant: questions
- Is Claude Opus 4.6 better than GPT-5.5 Instant?
- Claude Opus 4.6 leads on quality: 63.3 vs 60.5. The BenchLeader Index combines every independent quality benchmark; Claude Opus 4.6 is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is Claude Opus 4.6 better than GPT-5.5 Instant for coding?
- Claude Opus 4.6 scores higher in coding (62 vs 61 on the category index, where 50 is average).
- Is Claude Opus 4.6 better than GPT-5.5 Instant for agentic tasks?
- GPT-5.5 Instant scores higher in agentic tasks (71 vs 69 on the category index, where 50 is average).
- Which is cheaper, Claude Opus 4.6 or GPT-5.5 Instant?
- Claude Opus 4.6 is cheaper: $10.00 against $11.25 per million tokens, blended at three input tokens per output token.
- Which is faster, Claude Opus 4.6 or GPT-5.5 Instant?
- GPT-5.5 Instant streams faster: 129 against 36 output tokens per second.
- Which has the larger context window?
- Claude Opus 4.6 accepts more context: 1M against 400k tokens.