GPT-5.4 Pro vs GPT-5.5 Instant
GPT-5.4 Pro Verdict
- GPT-5.4 Pro leads on quality: 64.3 vs 60.5.
- GPT-5.4 Pro is stronger in knowledge, multimodal, reasoning.
- GPT-5.5 Instant is stronger in instruction following, agents & tools, coding, composite, human preference, long context, maths.
- GPT-5.5 Instant is 6.0× cheaper ($11.25 vs $67.50 per 1M blended).
- GPT-5.5 Instant streams 128.5× faster (129 vs 1 tokens per second).
| Metric | GPT-5.4 Pro | GPT-5.5 Instant |
|---|---|---|
| BenchLeader Index | 64.3 | 60.5 |
| Instruction following score | 67.3 | 69.8 |
| Knowledge score | 73.6 | 69.4 |
| Multimodal score | 69.8 | 59.7 |
| Reasoning score | 75.3 | 62.6 |
| Agents & tools score | – | 70.7 |
| Coding score | – | 61.1 |
| Composite score | – | 62.9 |
| Human preference score | – | 67.5 |
| Long context score | – | 61.4 |
| Maths score | – | 42.5 |
| Blended price $/M | $67.50 | $11.25 |
| Output speed | 1 tok/s | 129 tok/s |
| Time to first answer | 6.5 s | 16.8 s |
| Context window | 1.1M | 400k |
| GPQA Diamond | – | 82.5% |
| FrontierMath Tiers 1–3 | – | 26.3% |
| FrontierMath Tier 4 | – | 2.4% |
| OTIS Mock AIME | – | 68.1% |
| Humanity's Last Exam | 44.3% | – |
| SimpleBench | 74.1% | – |
| SciCode | – | 48.6% |
| Epoch Capabilities Index | 158.9 | 142.5 |
| LMArena Text | – | 1474 |
| LMArena Hard Prompts | – | 1491 |
| LMArena Coding | – | 1514 |
| LMArena Vision | – | 1251 |
| AA Intelligence Index | – | 26.8 |
| IFBench | – | 71.5% |
| AA-LCR | – | 70.0% |
| AA-Omniscience | – | 11.2 |
| Terminal-Bench Hard | – | 42.4% |
| GPQA Diamond (AA) | – | 84.7% |
| Humanity's Last Exam (AA) | – | 21.6% |
| SciCode (AA) | – | 52.5% |
| τ²-Bench Telecom (AA) | – | 49.4% |
| MultiChallenge | 69.2% | – |
| VISTA | 53.9% | – |
| MultiNRC | 62.3% | – |
| 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-5.4 Pro vs GPT-5.5 Instant: questions
- Is GPT-5.4 Pro better than GPT-5.5 Instant?
- GPT-5.4 Pro leads on quality: 64.3 vs 60.5. 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-5.4 Pro or GPT-5.5 Instant?
- GPT-5.5 Instant is cheaper: $11.25 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.4 Pro or GPT-5.5 Instant?
- GPT-5.5 Instant streams faster: 129 against 1 output tokens per second.
- Which has the larger context window?
- GPT-5.4 Pro accepts more context: 1.1M against 400k tokens.