Claude Sonnet 4.5 vs GPT-5.5
Head to head on 26 shared benchmarks, with price, context window, and release dates.
Benchmark scores
108evals · sort by any column, ⤢ to expand fullscreen
| Model | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GPT-5.5 OpenAI | 68.4% | 1844elo | 78.2 | 51.7% | 76.8% | 13.7% | 46.1% | 84.7% | 82.5% | 81.1% | 73.0% | 87.7% | 96.3% | 87.7% | 49.1% | 86.9% | 88.6% | 68.8% | 78.7% | 50.0% | 51.5% | 47.3% | 75.0% | 49.2% | 69.8% | 69.3% | - | - | - | - | - | 86.2% | 54.2% | - | - | 12.9% | - | 36.2% | - | - | - | 86.0% | 90.0% | 100.0% | - | - | 1315elo | 34.0% | - | - | 51.8% | 5.7% | 44.8% | - | 24.9% | 1769elo | - | - | 15.1% | - | - | - | 51.8% | - | - | - | - | 2.1% | - | - | - | - | - | - | 92.8% | - | - | - | - | - | 45.3% | 100.0% | - | - | - | - | - | - | - | 4.2 | - | - | - | - | - | - | 58.6% | - | - | - | 75.7% | - | 83.4% | - | 57.4% | 68.1% | - | - | 61.9% |
| Claude Sonnet 4.5 Anthropic | 60.8% | 1675elo | 71.4 | 15.2% | 72.7% | 7.2% | 42.7% | 70.7% | 80.4% | 57.0% | 53.4% | 76.5% | 79.3% | 77.6% | 40.6% | 84.5% | 86.0% | 64.0% | 62.9% | 19.0% | 32.9% | 42.8% | 73.3% | 28.8% | 22.6% | 70.5% | 0.0% | 0.0% | 37.0% | 100 | 0.0% | - | - | 0.0% | 0.0% | - | 5.0% | - | 0.0% | 0.0% | 0.0% | - | - | - | 0.0% | 0.0% | - | - | 0.0% | 0.0% | - | - | - | 0.0% | - | - | 0.0% | 83.9% | - | 0.0% | 0.0% | 0.0% | - | 0.0% | 0.0% | 87.5% | 83.8% | - | 0.0% | 0.0% | 59.0% | 0.75 | 0.75 | 0.0% | - | 0 | 0 | 0.0% | 0.0% | 0.0% | - | - | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | 0.0% | - | 0 | 0.0% | 0.0% | 77.2% | 67.0% | 74.8% | - | 0.0% | 0 | 0 | - | 50.34 | - | 0 | - | - | 0.0% | 1.49 | 27.5% |
2 / 2 models
| Attribute | Claude Sonnet 4.5 Anthropic | GPT-5.5 OpenAI |
|---|---|---|
| Description | anthropic/claude-sonnet-4.5 is an AI model. | GPT-5.5 is an AI model from OpenAI. |
| Family | Claude | GPT |
| Params | Undisclosed (closed) | - |
| Open weights | closed | closed |
| License | Proprietary | proprietary |
| Released | 29 Sep 2025 | 23 Apr 2026 |
| Context | 1,000,000 | 1,050,000 |
| Input $/1M | $3.00 | $5.00 |
| Output $/1M | $15.00 | $30.00 |
| Cache read $/1M | $0.300 | $0.500 |
| Cache write $/1M | $3.750 | - |
| Speed | 0 tok/s | 0 tok/s |
| Latency | 0.00 s | 0.00 s |
| Modalities | text, image, file | file, image, text |
| Providers | anthropic, aws-bedrock, vertex-ai | - |
| Publisher | Anthropic | OpenAI |
| Reported scores | TaxEval v273.3% LiveBench - Math79.3% (LiveBench) LiveBench - Coding80.4% (LiveBench) LiveBench - Language76.5% (LiveBench) LiveBench - Data Analysis57.0% (LiveBench) | GPQA Diamond76.8% (AA) Humanity's Last Exam (HLE)13.7% (AA) IFBench46.1% (AA) SciCode47.3% (AA) τ²-bench (Tau²-bench)69.3% (AA) |
FAQ
- Is Claude Sonnet 4.5 or GPT-5.5 better?
- Across the 26 benchmarks both models report on Sophon, GPT-5.5 leads on 25 of them. Which one is "better" depends on the benchmark - the table above shows every shared score.
- How do Claude Sonnet 4.5 and GPT-5.5 compare on GPQA Diamond?
- Claude Sonnet 4.5 scores 72.7% and GPT-5.5 scores 76.8% on GPQA Diamond.
- Which is cheaper, Claude Sonnet 4.5 or GPT-5.5?
- Claude Sonnet 4.5 is cheaper at $15.00 per million output tokens against $30.00 for GPT-5.5 - about 2.0x.
- When were Claude Sonnet 4.5 and GPT-5.5 released?
- Claude Sonnet 4.5 was released 29 Sep 2025 by Anthropic. GPT-5.5 was released 23 Apr 2026 by OpenAI.
Comparing something else? Build your own side-by-side.