GPT-5.6 Terra vs Grok 4
GPT-5.6 Terra 
Grok 4 Verdict
- GPT-5.6 Terra (xhigh) leads on quality: 62.6 vs 59.8.
- GPT-5.6 Terra (xhigh) is stronger in agents & tools, coding, composite, human preference, knowledge, maths, multimodal, reasoning.
- Grok 4 is stronger in instruction following, long context.
- Grok 4 is 2.9× cheaper ($1.56 vs $4.50 per 1M blended).
| Metric | GPT-5.6 Terra (xhigh) | Grok 4 |
|---|---|---|
| BenchLeader Index | 62.6 | 59.8 |
| Agents & tools score | 66.9 | 53.4 |
| Coding score | 61.5 | 61.2 |
| Composite score | 70.6 | – |
| Human preference score | 66.5 | 59.8 |
| Instruction following score | 62.1 | 67.7 |
| Knowledge score | 59.9 | 56.0 |
| Long context score | 63.5 | 77.7 |
| Maths score | 71.0 | 58.0 |
| Multimodal score | 62.4 | 54.5 |
| Reasoning score | 58.6 | 58.3 |
| Blended price $/M | $4.50 | $1.56 |
| Output speed | 97 tok/s | – |
| Time to first answer | 24.9 s | – |
| Context window | 1.1M | 256k |
| GPQA Diamond | – | 87.0% |
| OTIS Mock AIME | – | 84.0% |
| Terminal-Bench | – | 27.2% |
| SimpleBench | 48.9% | 60.5% |
| Fiction.LiveBench 120k | – | 96.9% |
| SciCode | 51.6% | – |
| Cybench | – | 43.0% |
| WeirdML | – | 45.7% |
| APEX-Agents | – | 15.2% |
| ProofBench | 74.0% | – |
| Epoch Capabilities Index | – | 146.4 |
| LMArena Text | 1466 | 1411 |
| LMArena Hard Prompts | 1489 | 1420 |
| LMArena Coding | 1518 | 1435 |
| LMArena WebDev | 1521 | – |
| LMArena Vision | 1269 | 1210 |
| LMArena Agent | 1.5 | – |
| AA Intelligence Index | 38.2 | – |
| IFBench | 66.3% | – |
| AA-LCR | 79.0% | – |
| MMMU-Pro | 79.5% | – |
| AA-Omniscience | -3.0 | – |
| Terminal-Bench Hard | 62.9% | – |
| GPQA Diamond (AA) | 90.8% | – |
| Humanity's Last Exam (AA) | 41.9% | – |
| SciCode (AA) | 52.3% | – |
| τ²-Bench Telecom (AA) | 80.4% | – |
| AIME (Vals) | – | 90.6% |
| LiveCodeBench | 85.9% | 83.3% |
| MMLU-Pro | 86.7% | 85.3% |
| LegalBench | – | 83.2% |
| CorpFin | 65.3% | 66.0% |
| TaxEval | 76.2% | 65.1% |
| MedQA | – | 92.5% |
| MGSM | – | 90.9% |
| SWE-bench (Vals) | – | 57.8% |
| GPQA Diamond (Vals) | 90.9% | 88.1% |
| IMO 2025 | – | 21.4% |
| MathArena Apex | – | 2.1% |
| Kagi LLM Benchmark | – | 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 | 94.0% | 79.6% |
| ARC-AGI-2 | 74.2% | 29.4% |
| ARC-AGI-3 | 0.7% | – |
| BFCL Overall | – | 63.0% |
Data as of 2026-09-13. Best configuration of each model; every score links to its source on the model pages.
GPT-5.6 Terra vs Grok 4: questions
- Is GPT-5.6 Terra better than Grok 4?
- GPT-5.6 Terra (xhigh) leads on quality: 62.6 vs 59.8. The BenchLeader Index combines every independent quality benchmark; GPT-5.6 Terra (xhigh) is ahead overall as of 2026-09-13, but check the category scores for your use.
- Is GPT-5.6 Terra better than Grok 4 for coding?
- GPT-5.6 Terra scores higher in coding (62 vs 61 on the category index, where 50 is average).
- Is GPT-5.6 Terra better than Grok 4 for agentic tasks?
- GPT-5.6 Terra scores higher in agentic tasks (67 vs 53 on the category index, where 50 is average).
- Which is cheaper, GPT-5.6 Terra or Grok 4?
- Grok 4 is cheaper: $1.56 against $4.50 per million tokens, blended at three input tokens per output token.
- Which has the larger context window?
- GPT-5.6 Terra accepts more context: 1.1M against 256k tokens.