GPT-5.5 vs gpt-oss-120b
Head to head on 19 shared benchmarks, with price, context window, and release dates.
Benchmark scores
64evals · sort by any column, ⤢ to expand fullscreen
| Model | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GPT-5.5 OpenAI | 68.4% | 86.0% | 1844elo | 78.2 | 76.8% | 13.7% | 46.1% | 84.7% | 82.5% | 81.1% | 73.0% | 87.7% | 96.3% | 87.7% | 88.6% | 47.3% | 75.0% | 49.2% | 69.3% | - | - | 86.2% | 54.2% | 12.9% | - | - | 36.2% | 90.0% | 100.0% | 1315elo | 34.0% | 51.8% | 5.7% | 51.7% | 44.8% | 24.9% | 1769elo | 15.1% | - | 51.8% | 2.1% | - | - | - | 92.8% | 49.1% | 86.9% | - | 68.8% | 78.7% | 45.3% | 100.0% | 50.0% | 51.5% | 4.2 | - | - | 58.6% | 75.7% | 83.4% | - | 57.4% | 68.1% | 69.8% | 61.9% |
| gpt-oss-120b OpenAI | 58.2% | 13.0% | 959elo | 35.8 | 67.2% | 5.9% | 58.3% | 51.0% | 60.2% | 38.8% | 50.3% | 48.6% | 68.9% | 39.2% | 77.5% | 36.0% | 71.6% | 5.3% | 45.0% | 41.8% | 66.7% | - | - | - | 38.9% | 7.6% | - | - | - | - | - | - | - | - | - | - | - | - | 57.6 | - | - | 70.7% | 1.62 | 1.53 | - | - | - | 80.0% | - | - | - | - | - | - | - | 97.9% | 26.0% | - | - | - | 65.6% | - | - | - | 49.6% |
2 / 2 models
| Attribute | GPT-5.5 OpenAI | gpt-oss-120b OpenAI |
|---|---|---|
| Description | GPT-5.5 is an AI model from OpenAI. | GPT-Oss 120b is an AI model from OpenAI, released with open weights. |
| Family | GPT | GPT |
| Params | - | - |
| Open weights | closed | open |
| License | proprietary | apache-2.0 |
| Released | 23 Apr 2026 | 5 Aug 2025 |
| Context | 1,050,000 | 131,072 |
| Input $/1M | $5.00 | $0.15 |
| Output $/1M | $30.00 | $0.60 |
| Cache read $/1M | $0.500 | $0.030 |
| Cache write $/1M | - | - |
| Speed | 0 tok/s | 186 tok/s |
| Latency | 0.00 s | 0.50 s |
| Modalities | file, image, text | text |
| Providers | - | - |
| Publisher | OpenAI | OpenAI |
| Reported scores | 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) | GPQA Diamond67.2% (AA) Humanity's Last Exam (HLE)5.9% (AA) LiveCodeBench70.7% (AA) MMLU-Pro77.5% (AA) SciCode36.0% (AA) |
FAQ
- Is GPT-5.5 or gpt-oss-120b better?
- Across the 19 benchmarks both models report on Sophon, GPT-5.5 leads on 18 of them. Which one is "better" depends on the benchmark - the table above shows every shared score.
- How do GPT-5.5 and gpt-oss-120b compare on GPQA Diamond?
- GPT-5.5 scores 76.8% and gpt-oss-120b scores 67.2% on GPQA Diamond.
- Which is cheaper, GPT-5.5 or gpt-oss-120b?
- gpt-oss-120b is cheaper at $0.60 per million output tokens against $30.00 for GPT-5.5 - about 50.0x.
- When were GPT-5.5 and gpt-oss-120b released?
- GPT-5.5 was released 23 Apr 2026 by OpenAI. gpt-oss-120b was released 5 Aug 2025 by OpenAI.
Comparing something else? Build your own side-by-side.