Gemini 3 Pro Turbo vs GPT-5.1 Turbo: which model should you choose?
We compared Gemini 3 Pro Turbo and GPT-5.1 Turbo on price, context window and 12 benchmarks. Gemini 3 Pro Turbo has the stronger average benchmark score; GPT-5.1 Turbo is cheaper on a blended 3:1 basis.
Gemini 3 Pro Turbo
Gemini 3 Pro Turbo is a frontier model from Google DeepMind. It offers a 400,000-token context window, costs $19.62 per million input tokens and $89.91 per million output tokens, and averages 86.4 across the index's benchmark suite.
- Input
- $19.62 / 1M
- Output
- $89.91 / 1M
- Context
- 400,000
- Avg score
- 86.4
- Open weights
- No
GPT-5.1 Turbo
GPT-5.1 Turbo is a frontier model from OpenAI. It offers a 2,000,000-token context window, costs $19.19 per million input tokens and $89.83 per million output tokens, and averages 86.1 across the index's benchmark suite.
- Input
- $19.19 / 1M
- Output
- $89.83 / 1M
- Context
- 2,000,000
- Avg score
- 86.1
- Open weights
- No
Specification comparison
| Spec | Gemini 3 Pro Turbo | GPT-5.1 Turbo | Edge |
|---|---|---|---|
| Input price / 1M | $19.62 | $19.19 | B |
| Output price / 1M | $89.91 | $89.83 | B |
| Context window | 400,000 | 2,000,000 | B |
| Max output | 16,384 | 128,000 | B |
| Average score | 86.4 | 86.1 | A |
| Arena Elo | 1494.9 | 1482.0 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Gemini 3 Pro Turbo wins 6, GPT-5.1 Turbo wins 5, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Gemini 3 Pro Turbo | GPT-5.1 Turbo | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 85.6 | 85.2 | 0.4 | Gemini 3 Pro Turbo |
| GPQA Diamond | 81.0 | 81.3 | 0.3 | GPT-5.1 Turbo |
| SWE-bench Verified | 77.4 | 74.7 | 2.7 | Gemini 3 Pro Turbo |
| HumanEval | 90.3 | 91.5 | 1.2 | GPT-5.1 Turbo |
| MATH-500 | 92.4 | 91.4 | 1.0 | Gemini 3 Pro Turbo |
| AIME 2025 | 82.8 | 84.7 | 1.9 | GPT-5.1 Turbo |
| LiveCodeBench | 82.7 | 84.6 | 1.9 | GPT-5.1 Turbo |
| IFEval | 93.4 | 93.4 | 0.0 | Tie |
| TruthfulQA | 87.8 | 89.2 | 1.4 | GPT-5.1 Turbo |
| HellaSwag | 94.6 | 91.3 | 3.3 | Gemini 3 Pro Turbo |
| MMMU | 82.7 | 79.7 | 3.0 | Gemini 3 Pro Turbo |
| Arena Elo | 1494.9 | 1482.0 | 12.9 | Gemini 3 Pro Turbo |
Price analysis
On a blended 3:1 input-to-output basis, Gemini 3 Pro Turbo costs about $37.19 per million tokens and GPT-5.1 Turbo costs about $36.85. GPT-5.1 Turbo is roughly 1% cheaper than Gemini 3 Pro Turbo. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
GPT-5.1 Turbo has the larger context window at 2,000,000 tokens, compared with 400,000 for Gemini 3 Pro Turbo. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Gemini 3 Pro Turbo wins 6, GPT-5.1 Turbo wins 5, and 1 are tied. On the index average, Gemini 3 Pro Turbo leads GPT-5.1 Turbo by 0.3 points (86.4 versus 86.1).
The price picture favours GPT-5.1 Turbo. The context picture favours GPT-5.1 Turbo. Those two dimensions often matter more than a few benchmark points once a model is good enough for the task.
If you need a single default, start with Gemini 3 Pro Turbo for quality-sensitive work and GPT-5.1 Turbo for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose Gemini 3 Pro Turbo if
- You want the higher average benchmark score in this index.
Choose GPT-5.1 Turbo if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 2,000,000-token context window.
- You need the larger 128,000-token output limit.
FAQ
Is Gemini 3 Pro Turbo better than GPT-5.1 Turbo?
On the index average, Gemini 3 Pro Turbo leads GPT-5.1 Turbo by 0.3 points (86.4 versus 86.1). The better choice depends on price, context and your task. Gemini 3 Pro Turbo wins 6 benchmarks, GPT-5.1 Turbo wins 5.
Which is cheaper, Gemini 3 Pro Turbo or GPT-5.1 Turbo?
GPT-5.1 Turbo is cheaper on a blended 3:1 basis at about $36.85 per million tokens, versus $37.19 for Gemini 3 Pro Turbo.
Which has the larger context window?
GPT-5.1 Turbo has the larger context window at 2,000,000 tokens. Gemini 3 Pro Turbo has 400,000 tokens.
Are these models open weights?
Gemini 3 Pro Turbo is proprietary; GPT-5.1 Turbo is proprietary.
Which should I choose for production?
If you need a single default, start with Gemini 3 Pro Turbo for quality-sensitive work and GPT-5.1 Turbo for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.