GPT-5.5 vs GPT-5 Pro
GPT-5.5 Verdict
- GPT-5.5 leads on quality: 66.7 vs 60.8.
- GPT-5.5 is stronger in agents & tools, coding, composite, human preference, instruction following, knowledge, long context, reasoning.
- GPT-5 Pro is stronger in multimodal.
- GPT-5.5 is 3.7× cheaper ($11.25 vs $41.25 per 1M blended).
| Metric | GPT-5.5 | GPT-5 Pro |
|---|---|---|
| BenchLeader Index | 66.7 | 60.8 |
| Agents & tools score | 68.5 | – |
| Coding score | 57.2 | – |
| Composite score | 77.8 | – |
| Human preference score | 67.9 | – |
| Instruction following score | 73.6 | – |
| Knowledge score | 73.9 | 68.0 |
| Long context score | 68.8 | – |
| Multimodal score | 64.9 | 67.4 |
| Reasoning score | 70.1 | 57.6 |
| Blended price $/M | $11.25 | $41.25 |
| Output speed | 85 tok/s | – |
| Time to first answer | 58.6 s | – |
| Context window | 1.1M | 400k |
| Humanity's Last Exam | – | 31.6% |
| Terminal-Bench | 84.7% | – |
| SimpleBench | 69.0% | 61.6% |
| Remote Labor Index | 6.3% | – |
| APEX-Agents | 38.5% | – |
| FrontierCode | 43.0% | – |
| Epoch Capabilities Index | 159.1 | 150.3 |
| LMArena Text | 1477 | – |
| LMArena Hard Prompts | 1498 | – |
| LMArena Coding | 1509 | – |
| LMArena WebDev | 1458 | – |
| LMArena Vision | 1296 | – |
| LMArena Agent | 3 | – |
| AA Intelligence Index | 38.6 | – |
| IFBench | 75.8% | – |
| AA-LCR | 84.3% | – |
| MMMU-Pro | 79.9% | – |
| AA-Omniscience | 20.5 | – |
| Terminal-Bench Hard | 60.6% | – |
| GPQA Diamond (AA) | 93.5% | – |
| Humanity's Last Exam (AA) | 45.8% | – |
| SciCode (AA) | 55.8% | – |
| τ²-Bench Telecom (AA) | 93.9% | – |
| PRBench Finance | – | 51.1% |
| PRBench Legal | – | 49.9% |
| VISTA | – | 52.4% |
| MultiNRC | – | 65.2% |
| HiL-Bench | 39.7% | – |
| EQ-Bench 4 | 1315 | – |
| Kagi LLM Benchmark | 88.8% | 76.8% |
| ARC-AGI-1 | – | 70.2% |
| ARC-AGI-2 | – | 18.3% |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 vs GPT-5 Pro: questions
- Is GPT-5.5 better than GPT-5 Pro?
- GPT-5.5 leads on quality: 66.7 vs 60.8. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 is ahead overall as of 2026-09-10, but check the category scores for your use.
- Which is cheaper, GPT-5.5 or GPT-5 Pro?
- GPT-5.5 is cheaper: $11.25 against $41.25 per million tokens, blended at three input tokens per output token.
- Which has the larger context window?
- GPT-5.5 accepts more context: 1.1M against 400k tokens.