GPT-5.4 (2026-03-05) vs GPT-5.5
Humanity's Last Exam Humanity's Last Exam: Very hard expert questions across many fields, written to stump today’s models
GPT-5.4 (2026-03-05)—
GPT-5.542.4
Terminal-Bench 4.0 Terminal-Bench 4.0 · source setting 2: Agents use a terminal to complete executable coding, system administration and research tasks in the 4.0 suite
GPT-5.4 (2026-03-05)—
GPT-5.55.1
AutomationBench-AA AutomationBench-AA: Agents orchestrate SaaS workflows through APIs; objectives receive credit only when the task has no guardrail violation
GPT-5.4 (2026-03-05)—
GPT-5.540.1
Arena Text · creative writing Arena Text · creative writing: Human pairwise preferences in the stated text vote pool
GPT-5.4 (2026-03-05)—
GPT-5.5 · high1,451
MMMU-Pro (vision) MMMU-Pro (vision): College-level questions that require understanding images: charts, diagrams, photos
GPT-5.4 (2026-03-05)—
GPT-5.581.2
| Benchmark | GPT-5.4 (2026-03-05) | GPT-5.5 |
|---|---|---|
| Humanity's Last Exam | — | 42.4 |
| Terminal-Bench 4.0 | — | 5.1 |
| AutomationBench-AA | — | 40.1 |
| Arena Text · creative writing | — | 1,451 · high |
| MMMU-Pro (vision) | — | 81.2 |
Specs
| Spec | GPT-5.4 (2026-03-05) | GPT-5.5 |
|---|---|---|
| Input, per 1M | !$2.50 | $5 |
| Output, per 1M | !$15 | $30 |
| Cost per task? | — | $0.90 |
| Speed, tok/s | — | 89 |
| Context | 1.05M | 1.05M |
| Weights | Not verified | Closed |
| Released | Mar 2026 | Apr 2026 |
| See images | ✓ | ✓ |
| Read PDFs | ? | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | ? | Partial |
| Return strict JSON | ✓ | ✓ |
| Search the web | ? | ? |
| Run code | ? | ? |
| Use a computer | ? | ? |
What breaks when you switch
GPT-5.4 (2026-03-05) → GPT-5.5
Prompts with >272K input tokens›
Above 272K input tokens, input costs 2× and output 1.5× for the full session in Standard, Batch and Flex.
GPT-5.5 → GPT-5.4 (2026-03-05)
Nothing known.