GPT-5.3-Codex vs GPT-5.4 Pro
GPT-5.3-Codex Verdict
- GPT-5.4 Pro leads on quality: 64.3 vs 62.5.
- GPT-5.3-Codex is stronger in agents & tools, coding, composite, instruction following, long context.
- GPT-5.4 Pro is stronger in knowledge, multimodal, reasoning.
- GPT-5.3-Codex is 14× cheaper ($4.81 vs $67.50 per 1M blended).
- GPT-5.3-Codex streams 121.3× faster (121 vs 1 tokens per second).
| Metric | GPT-5.3-Codex | GPT-5.4 Pro |
|---|---|---|
| BenchLeader Index | 62.5 | 64.3 |
| Agents & tools score | 62.7 | – |
| Coding score | 54.8 | – |
| Composite score | 70.1 | – |
| Instruction following score | 73.2 | 67.3 |
| Knowledge score | 69.3 | 73.6 |
| Long context score | 68.3 | – |
| Multimodal score | 63.0 | 69.8 |
| Reasoning score | – | 75.3 |
| Blended price $/M | $4.81 | $67.50 |
| Output speed | 121 tok/s | 1 tok/s |
| Time to first answer | 58.2 s | 6.5 s |
| Context window | 400k | 1.1M |
| Humanity's Last Exam | – | 44.3% |
| Terminal-Bench | 78.4% | – |
| SimpleBench | – | 74.1% |
| WeirdML | 79.3% | – |
| APEX-Agents | 31.8% | – |
| Epoch Capabilities Index | 156.6 | 158.9 |
| LMArena WebDev | 1409 | – |
| 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% | – |
| MultiChallenge | – | 69.2% |
| VISTA | – | 53.9% |
| MultiNRC | – | 62.3% |
| HiL-Bench | 4.3% | – |
| TutorBench | – | 56.6% |
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-5.4 Pro: questions
- Is GPT-5.3-Codex better than GPT-5.4 Pro?
- GPT-5.4 Pro leads on quality: 64.3 vs 62.5. The BenchLeader Index combines every independent quality benchmark; GPT-5.4 Pro is ahead overall as of 2026-09-10, but check the category scores for your use.
- Which is cheaper, GPT-5.3-Codex or GPT-5.4 Pro?
- GPT-5.3-Codex is cheaper: $4.81 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.3-Codex or GPT-5.4 Pro?
- GPT-5.3-Codex streams faster: 121 against 1 output tokens per second.
- Which has the larger context window?
- GPT-5.4 Pro accepts more context: 1.1M against 400k tokens.