GPT-5.5 vs Grok 4
GPT-5.5 
Grok 4 Verdict
- GPT-5.5 leads on quality: 66.7 vs 58.6.
- GPT-5.5 is stronger in agents & tools, composite, human preference, instruction following, knowledge, multimodal, reasoning.
- Grok 4 is stronger in coding, long context, maths.
- Grok 4 is 7.2× cheaper ($1.56 vs $11.25 per 1M blended).
| Metric | GPT-5.5 | Grok 4 |
|---|---|---|
| BenchLeader Index | 66.7 | 58.6 |
| Agents & tools score | 68.4 | 55.3 |
| Coding score | 57.2 | 61.2 |
| Composite score | 77.9 | 57.4 |
| Human preference score | 67.7 | 59.8 |
| Instruction following score | 73.6 | 62.4 |
| Knowledge score | 74.0 | 58.3 |
| Long context score | 68.8 | 69.0 |
| Multimodal score | 65.0 | 53.8 |
| Reasoning score | 70.0 | 58.3 |
| Maths score | – | 58.0 |
| Blended price $/M | $11.25 | $1.56 |
| Output speed | 85 tok/s | – |
| Time to first answer | 50.1 s | – |
| Context window | 1.1M | 256k |
| GPQA Diamond | – | 87.0% |
| OTIS Mock AIME | – | 84.0% |
| Terminal-Bench | 84.7% | 27.2% |
| SimpleBench | 69.0% | 60.5% |
| Fiction.LiveBench 120k | – | 96.9% |
| Cybench | – | 43.0% |
| Remote Labor Index | 6.3% | – |
| WeirdML | – | 45.7% |
| APEX-Agents | 38.5% | 15.2% |
| FrontierCode | 43.0% | – |
| Epoch Capabilities Index | 159.1 | 146.4 |
| LMArena Text | 1476 | 1411 |
| LMArena Hard Prompts | 1498 | 1420 |
| LMArena Coding | 1509 | 1435 |
| LMArena WebDev | 1458 | – |
| LMArena Vision | 1296 | 1210 |
| LMArena Agent | 2.8 | – |
| AA Intelligence Index | 38.6 | 22.5 |
| IFBench | 75.8% | 53.7% |
| AA-LCR | 84.3% | 68.0% |
| MMMU-Pro | 79.9% | 68.8% |
| AA-Omniscience | 20.5 | 2.1 |
| Terminal-Bench Hard | 60.6% | 37.9% |
| GPQA Diamond (AA) | 93.5% | 87.7% |
| Humanity's Last Exam (AA) | 45.8% | 26.7% |
| SciCode (AA) | 55.8% | – |
| τ²-Bench Telecom (AA) | 93.9% | 74.8% |
| AIME (Vals) | – | 90.6% |
| LiveCodeBench | – | 83.3% |
| MMLU-Pro | – | 85.3% |
| LegalBench | – | 83.2% |
| CorpFin | – | 66.0% |
| TaxEval | – | 65.1% |
| MedQA | – | 92.5% |
| MGSM | – | 90.9% |
| SWE-bench (Vals) | – | 57.8% |
| GPQA Diamond (Vals) | – | 88.1% |
| IMO 2025 | – | 21.4% |
| MathArena Apex | – | 2.1% |
| HiL-Bench | 39.7% | – |
| EQ-Bench 4 | 1315 | – |
| Kagi LLM Benchmark | 88.8% | 73.6% |
| IFEval (HELM) | – | 94.9% |
| Omni-MATH (HELM) | – | 60.3% |
| WildBench (HELM) | – | 79.7% |
| MMLU-Pro (HELM) | – | 85.1% |
| GPQA Diamond (HELM) | – | 72.6% |
| HELM Capabilities mean | – | 78.5% |
| Aider Polyglot | – | 79.6% |
| ARC-AGI-1 | – | 79.6% |
| ARC-AGI-2 | – | 29.4% |
| BFCL Overall | – | 63.0% |
Data as of 2026-09-12. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 vs Grok 4: questions
- Is GPT-5.5 better than Grok 4?
- GPT-5.5 leads on quality: 66.7 vs 58.6. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 is ahead overall as of 2026-09-12, but check the category scores for your use.
- Is GPT-5.5 better than Grok 4 for coding?
- Grok 4 scores higher in coding (61 vs 57 on the category index, where 50 is average).
- Is GPT-5.5 better than Grok 4 for agentic tasks?
- GPT-5.5 scores higher in agentic tasks (68 vs 55 on the category index, where 50 is average).
- Which is cheaper, GPT-5.5 or Grok 4?
- Grok 4 is cheaper: $1.56 against $11.25 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 256k tokens.