GPT-5.3-Codex vs Grok 4
GPT-5.3-Codex 
Grok 4 Verdict
- GPT-5.3-Codex and Grok 4 are level on quality (60.6 vs 59.8).
- GPT-5.3-Codex is stronger in agents & tools, composite, instruction following, knowledge, multimodal.
- Grok 4 is stronger in coding, long context, human preference, maths, reasoning.
- Grok 4 is 3.1× cheaper ($1.56 vs $4.81 per 1M blended).
| Metric | GPT-5.3-Codex | Grok 4 |
|---|---|---|
| BenchLeader Index | 60.6 | 59.8 |
| Agents & tools score | 61.7 | 53.4 |
| Coding score | 54.7 | 61.2 |
| Composite score | 64.0 | – |
| Instruction following score | 70.1 | 67.7 |
| Knowledge score | 65.9 | 56.0 |
| Long context score | 66.0 | 77.7 |
| Multimodal score | 61.6 | 54.5 |
| Human preference score | – | 59.8 |
| Maths score | – | 58.0 |
| Reasoning score | – | 58.3 |
| Blended price $/M | $4.81 | $1.56 |
| Output speed | 124 tok/s | – |
| Time to first answer | 48.3 s | – |
| Context window | 400k | 256k |
| GPQA Diamond | – | 87.0% |
| OTIS Mock AIME | – | 84.0% |
| Terminal-Bench | 78.4% | 27.2% |
| SimpleBench | – | 60.5% |
| Fiction.LiveBench 120k | – | 96.9% |
| Cybench | – | 43.0% |
| WeirdML | 79.3% | 45.7% |
| APEX-Agents | 31.8% | 15.2% |
| Epoch Capabilities Index | 156.6 | 146.4 |
| LMArena Text | – | 1411 |
| LMArena Hard Prompts | – | 1420 |
| LMArena Coding | – | 1435 |
| LMArena WebDev | 1409 | – |
| LMArena Vision | – | 1210 |
| AA Intelligence Index | 32.5 | – |
| IFBench | 75.4% | – |
| AA-LCR | 83.3% | – |
| MMMU-Pro | 78.5% | – |
| AA-Omniscience | 10.9 | – |
| Terminal-Bench Hard | 53.0% | – |
| GPQA Diamond (AA) | 91.5% | – |
| Humanity's Last Exam (AA) | 42.5% | – |
| τ²-Bench Telecom (AA) | 86.0% | – |
| 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 | 4.3% | – |
| 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 | – | 79.6% |
| ARC-AGI-2 | – | 29.4% |
| 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-5.3-Codex vs Grok 4: questions
- Is GPT-5.3-Codex better than Grok 4?
- GPT-5.3-Codex and Grok 4 are level on quality (60.6 vs 59.8). The BenchLeader Index combines every independent quality benchmark; GPT-5.3-Codex is ahead overall as of 2026-09-13, but check the category scores for your use.
- Is GPT-5.3-Codex better than Grok 4 for coding?
- Grok 4 scores higher in coding (61 vs 55 on the category index, where 50 is average).
- Is GPT-5.3-Codex better than Grok 4 for agentic tasks?
- GPT-5.3-Codex scores higher in agentic tasks (62 vs 53 on the category index, where 50 is average).
- Which is cheaper, GPT-5.3-Codex or Grok 4?
- Grok 4 is cheaper: $1.56 against $4.81 per million tokens, blended at three input tokens per output token.
- Which has the larger context window?
- GPT-5.3-Codex accepts more context: 400k against 256k tokens.