GPT-5.4 vs GPT-5.5 Instant
GPT-5.4 Verdict
- GPT-5.4 leads on quality: 63.5 vs 60.5.
- GPT-5.4 is stronger in composite, instruction following, long context, multimodal.
- GPT-5.5 Instant is stronger in agents & tools, coding, human preference, knowledge, maths.
- GPT-5.4 is 2.0× cheaper ($5.63 vs $11.25 per 1M blended).
| Metric | GPT-5.4 | GPT-5.5 Instant |
|---|---|---|
| BenchLeader Index | 63.5 | 60.5 |
| Agents & tools score | 66.2 | 70.7 |
| Coding score | 51.6 | 61.1 |
| Composite score | 78.3 | 62.9 |
| Human preference score | 64.7 | 67.5 |
| Instruction following score | 71.9 | 69.8 |
| Knowledge score | 66.9 | 69.4 |
| Long context score | 67.6 | 61.4 |
| Multimodal score | 64.0 | 59.7 |
| Reasoning score | 62.6 | 62.6 |
| Maths score | – | 42.5 |
| Blended price $/M | $5.63 | $11.25 |
| Output speed | 129 tok/s | 129 tok/s |
| Time to first answer | 124.6 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% |
| Terminal-Bench | 81.8% | – |
| SciCode | – | 48.6% |
| APEX-Agents | 34.9% | – |
| Epoch Capabilities Index | 156.9 | 142.5 |
| LMArena Text | 1466 | 1474 |
| LMArena Hard Prompts | 1488 | 1491 |
| LMArena Coding | 1514 | 1514 |
| LMArena WebDev | 1386 | – |
| LMArena Vision | 1293 | 1251 |
| AA Intelligence Index | 39.0 | 26.8 |
| IFBench | 74.0% | 71.5% |
| AA-LCR | 82.0% | 70.0% |
| MMMU-Pro | 78.4% | – |
| AA-Omniscience | 5.8 | 11.2 |
| Terminal-Bench Hard | 57.6% | 42.4% |
| GPQA Diamond (AA) | 92.0% | 84.7% |
| Humanity's Last Exam (AA) | 43.7% | 21.6% |
| SciCode (AA) | – | 52.5% |
| τ²-Bench Telecom (AA) | 87.1% | 49.4% |
| HiL-Bench | 9.7% | – |
| EQ-Bench 4 | 1272 | – |
| Kagi LLM Benchmark | 63.8% | – |
Data as of 2026-09-10. Best configuration of each model; every score links to its source on the model pages.
GPT-5.4 vs GPT-5.5 Instant: questions
- Is GPT-5.4 better than GPT-5.5 Instant?
- GPT-5.4 leads on quality: 63.5 vs 60.5. The BenchLeader Index combines every independent quality benchmark; GPT-5.4 is ahead overall as of 2026-09-10, but check the category scores for your use.
- Is GPT-5.4 better than GPT-5.5 Instant for coding?
- GPT-5.5 Instant scores higher in coding (61 vs 52 on the category index, where 50 is average).
- Is GPT-5.4 better than GPT-5.5 Instant for agentic tasks?
- GPT-5.5 Instant scores higher in agentic tasks (71 vs 66 on the category index, where 50 is average).
- Which is cheaper, GPT-5.4 or GPT-5.5 Instant?
- GPT-5.4 is cheaper: $5.63 against $11.25 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.4 or GPT-5.5 Instant?
- GPT-5.4 streams faster: 129 against 129 output tokens per second.
- Which has the larger context window?
- GPT-5.4 accepts more context: 1.1M against 400k tokens.