GPT-5.3-Codex vs GPT-6 Astra
GPT-5.3-Codex Verdict
- GPT-6 Astra (max) leads on quality: 70.9 vs 62.5.
- GPT-5.3-Codex is stronger in instruction following, long context, multimodal.
- GPT-6 Astra (max) is stronger in agents & tools, coding, composite, knowledge, maths, reasoning.
- GPT-5.3-Codex is 4.2× cheaper ($4.81 vs $20.00 per 1M blended).
- GPT-5.3-Codex streams 4.5× faster (121 vs 27 tokens per second).
| Metric | GPT-5.3-Codex | GPT-6 Astra (max) |
|---|---|---|
| BenchLeader Index | 62.5 | 70.9 |
| Agents & tools score | 62.7 | 68.2 |
| Coding score | 54.8 | 78.6 |
| Composite score | 70.1 | 72.9 |
| Instruction following score | 73.2 | – |
| Knowledge score | 69.3 | 80.0 |
| Long context score | 68.3 | – |
| Multimodal score | 63.0 | – |
| Maths score | – | 77.2 |
| Reasoning score | – | 73.6 |
| Blended price $/M | $4.81 | $20.00 |
| Output speed | 121 tok/s | 27 tok/s |
| Time to first answer | 58.2 s | 337.3 s |
| Context window | 400k | 1.1M |
| GPQA Diamond | – | 95.8% |
| FrontierMath Tiers 1–3 | – | 93.7% |
| FrontierMath Tier 4 | – | 97.6% |
| OTIS Mock AIME | – | 100.0% |
| SimpleQA Verified | – | 75.6% |
| Terminal-Bench | 78.4% | 58.2% |
| SciCode | – | 56.5% |
| WeirdML | 79.3% | – |
| APEX-Agents | 31.8% | – |
| FrontierCode | – | 53.3% |
| Epoch Capabilities Index | 156.6 | – |
| LMArena WebDev | 1409 | 1796 |
| LMArena Agent | – | 12.5 |
| LiveBench | – | 82.2% |
| LiveBench Reasoning | – | 92.7% |
| LiveBench Coding | – | 80.4% |
| LiveBench Agentic Coding | – | 57.3% |
| LiveBench Mathematics | – | 96.8% |
| LiveBench Data Analysis | – | 83.0% |
| LiveBench Language | – | 89.4% |
| 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% | – |
| Terminal-Bench 2.1 (Vals) | – | 87.3% |
| Vals Index | – | 66.6 |
| HiL-Bench | 4.3% | – |
| ARC-AGI-1 | – | 97.5% |
| ARC-AGI-2 | – | 95.0% |
| ARC-AGI-3 | – | 98.6% |
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 GPT-6 Astra: questions
- Is GPT-5.3-Codex better than GPT-6 Astra?
- GPT-6 Astra (max) leads on quality: 70.9 vs 62.5. The BenchLeader Index combines every independent quality benchmark; GPT-6 Astra (max) is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.3-Codex better than GPT-6 Astra for coding?
- GPT-6 Astra scores higher in coding (79 vs 55 on the category index, where 50 is average).
- Is GPT-5.3-Codex better than GPT-6 Astra for agentic tasks?
- GPT-6 Astra scores higher in agentic tasks (68 vs 63 on the category index, where 50 is average).
- Which is cheaper, GPT-5.3-Codex or GPT-6 Astra?
- GPT-5.3-Codex is cheaper: $4.81 against $20.00 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.3-Codex or GPT-6 Astra?
- GPT-5.3-Codex streams faster: 121 against 27 output tokens per second.
- Which has the larger context window?
- GPT-6 Astra accepts more context: 1.1M against 400k tokens.