Claude Opus 4.1 vs Claude Opus 4.5
Humanity's Last Exam Humanity's Last Exam: Very hard expert questions across many fields, written to stump today’s models
Opus 4.112.5
Opus 4.513.2
Arena Text · creative writing Arena Text · creative writing: Human pairwise preferences in the stated text vote pool
Opus 4.11,446
Opus 4.5 · high1,469
MMMU-Pro (vision) MMMU-Pro (vision): College-level questions that require understanding images: charts, diagrams, photos
Opus 4.167.9
Opus 4.571.2
| Benchmark | Opus 4.1 | Opus 4.5 |
|---|---|---|
| Humanity's Last Exam | 12.5 | 13.2 |
| Arena Text · creative writing | 1,446 | 1,469 · high |
| MMMU-Pro (vision) | 67.9 | 71.2 |
Specs
| Spec | Opus 4.1 | Opus 4.5 |
|---|---|---|
| Input, per 1M | $15 | $5 |
| Output, per 1M | $75 | $25 |
| Speed, tok/s | — | 51 |
| Context | 200K | 200K |
| Weights | Closed | Closed |
| Released | Aug 2025 | Nov 2025 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | — | ✓ |
| Search the web | ? | ? |
| Run code | ? | ? |
| Use a computer | ? | ? |
What breaks when you switch
Opus 4.1 → Opus 4.5
Nothing known.
Opus 4.5 → Opus 4.1