GLM 5.1 vs GPT-5.5
Head to head on 31 shared benchmarks, with price, context window, and release dates.
Benchmark scores
56evals · sort by any column, ⤢ to expand fullscreen
| Model | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| GPT-5.5 OpenAI | 86.2% | 12.9% | 68.4% | 86.0% | 1844elo | 78.2 | 51.8% | 51.7% | 44.8% | 76.8% | 15.1% | 13.7% | 46.1% | 84.7% | 82.5% | 81.1% | 73.0% | 87.7% | 96.3% | 87.7% | 92.8% | 49.1% | 86.9% | 88.6% | 50.0% | 47.3% | 75.0% | 49.2% | 57.4% | 69.8% | 69.3% | 54.2% | - | 36.2% | 90.0% | 100.0% | 1315elo | 34.0% | 5.7% | 24.9% | 1769elo | 51.8% | 2.1% | 68.8% | 78.7% | 45.3% | 100.0% | 51.5% | - | - | 4.2 | 58.6% | 75.7% | 83.4% | - | 68.1% | 61.9% |
| GLM 5.1 Zai | 20.8% | 35.9% | 64.5% | 40.0% | 1589elo | 73.5 | 44.8% | 33.5% | 34.7% | 83.9% | 15.1% | 27.9% | 52.0% | 72.7% | 75.4% | 63.2% | 68.5% | 71.8% | 84.9% | 72.5% | 67.0% | 41.6% | 72.3% | 85.4% | 22.2% | 36.1% | 71.2% | 35.6% | 52.5% | 31.5% | 97.1% | - | 1.13 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 34.6% | 5.24 | - | - | - | - | 69.8 | - | 53.6% |
2 / 2 models
| Attribute | GLM 5.1 Zai | GPT-5.5 OpenAI |
|---|---|---|
| Description | GLM-5.1 is an AI model from Zai, released with open weights. | GPT-5.5 is an AI model from OpenAI. |
| Family | Glm | GPT |
| Params | - | - |
| Open weights | open | closed |
| License | mit | proprietary |
| Released | 7 Apr 2026 | 23 Apr 2026 |
| Context | 204,800 | 1,050,000 |
| Input $/1M | $1.39 | $5.00 |
| Output $/1M | $4.40 | $30.00 |
| Cache read $/1M | $0.234 | $0.500 |
| Cache write $/1M | - | - |
| Speed | 0 tok/s | 0 tok/s |
| Latency | 0.00 s | 0.00 s |
| Modalities | text | file, image, text |
| Providers | - | - |
| Publisher | Zai | OpenAI |
| Reported scores | IFBench52.0% (AA) τ²-bench (Tau²-bench)97.1% (AA) Terminal-Bench (Hard)35.6% (AA) Vals Index52.5% Vibe Code Bench v1.131.5% | 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 GLM 5.1 or GPT-5.5 better?
- Across the 31 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 GLM 5.1 and GPT-5.5 compare on GPQA Diamond?
- GLM 5.1 scores 83.9% and GPT-5.5 scores 76.8% on GPQA Diamond.
- Which is cheaper, GLM 5.1 or GPT-5.5?
- GLM 5.1 is cheaper at $4.40 per million output tokens against $30.00 for GPT-5.5 - about 6.8x.
- When were GLM 5.1 and GPT-5.5 released?
- GLM 5.1 was released 7 Apr 2026 by Zai. GPT-5.5 was released 23 Apr 2026 by OpenAI.
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