GPT-5.3-Codex vs Grok 4.6
GPT-5.3-Codex 
Grok 4.6 Verdict
- Grok 4.6 (medium) leads on quality: 63.9 vs 62.5.
- GPT-5.3-Codex is stronger in agents & tools, instruction following, long context, multimodal.
- Grok 4.6 (medium) is stronger in coding, composite, knowledge, reasoning.
- Grok 4.6 (medium) is 1.6× cheaper ($3.00 vs $4.81 per 1M blended).
- GPT-5.3-Codex streams 2.3× faster (121 vs 53 tokens per second).
| Metric | GPT-5.3-Codex | Grok 4.6 (medium) |
|---|---|---|
| BenchLeader Index | 62.5 | 63.9 |
| Agents & tools score | 62.7 | – |
| Coding score | 54.8 | 64.1 |
| Composite score | 70.1 | 83.4 |
| Instruction following score | 73.2 | – |
| Knowledge score | 69.3 | 77.5 |
| Long context score | 68.3 | 67.1 |
| Multimodal score | 63.0 | – |
| Reasoning score | – | 62.1 |
| Blended price $/M | $4.81 | $3.00 |
| Output speed | 121 tok/s | 53 tok/s |
| Time to first answer | 58.2 s | 33.4 s |
| Context window | 400k | 500k |
| Terminal-Bench | 78.4% | – |
| SciCode | – | 54.6% |
| WeirdML | 79.3% | – |
| APEX-Agents | 31.8% | – |
| Epoch Capabilities Index | 156.6 | – |
| LMArena WebDev | 1409 | – |
| AA Intelligence Index | 32.5 | 43.0 |
| IFBench | 75.4% | – |
| AA-LCR | 83.3% | 81.0% |
| MMMU-Pro | 78.5% | – |
| AA-Omniscience | 10.9 | 28 |
| Terminal-Bench Hard | 53.0% | – |
| GPQA Diamond (AA) | 91.5% | 93.5% |
| Humanity's Last Exam (AA) | 42.5% | 42.1% |
| SciCode (AA) | – | 55.9% |
| τ²-Bench Telecom (AA) | 86.0% | – |
| HiL-Bench | 4.3% | – |
| ARC-AGI-1 | – | 87.5% |
| ARC-AGI-2 | – | 61.3% |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.3-Codex vs Grok 4.6: questions
- Is GPT-5.3-Codex better than Grok 4.6?
- Grok 4.6 (medium) leads on quality: 63.9 vs 62.5. The BenchLeader Index combines every independent quality benchmark; Grok 4.6 (medium) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.3-Codex better than Grok 4.6 for coding?
- Grok 4.6 scores higher in coding (64 vs 55 on the category index, where 50 is average).
- Which is cheaper, GPT-5.3-Codex or Grok 4.6?
- Grok 4.6 is cheaper: $3.00 against $4.81 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.3-Codex or Grok 4.6?
- GPT-5.3-Codex streams faster: 121 against 53 output tokens per second.
- Which has the larger context window?
- Grok 4.6 accepts more context: 500k against 400k tokens.