GPT-5.1 vs GPT-5.1 Turbo: which model should you choose?
We compared GPT-5.1 and GPT-5.1 Turbo on price, context window and 12 benchmarks. GPT-5.1 Turbo has the stronger average benchmark score; GPT-5.1 is cheaper on a blended 3:1 basis.
GPT-5.1
GPT-5.1 is a frontier model from OpenAI. It offers a 2,000,000-token context window, costs $19.01 per million input tokens and $69.84 per million output tokens, and averages 86.0 across the index's benchmark suite.
- Input
- $19.01 / 1M
- Output
- $69.84 / 1M
- Context
- 2,000,000
- Avg score
- 86.0
- 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 | GPT-5.1 | GPT-5.1 Turbo | Edge |
|---|---|---|---|
| Input price / 1M | $19.01 | $19.19 | A |
| Output price / 1M | $69.84 | $89.83 | A |
| Context window | 2,000,000 | 2,000,000 | Tie |
| Max output | 128,000 | 128,000 | Tie |
| Average score | 86.0 | 86.1 | B |
| Arena Elo | 1462.5 | 1482.0 | B |
| Open weights | No | No | Tie |
Benchmark comparison
GPT-5.1 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 | GPT-5.1 | GPT-5.1 Turbo | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 86.1 | 85.2 | 0.9 | GPT-5.1 |
| GPQA Diamond | 82.3 | 81.3 | 1.0 | GPT-5.1 |
| SWE-bench Verified | 76.1 | 74.7 | 1.4 | GPT-5.1 |
| HumanEval | 90.6 | 91.5 | 0.9 | GPT-5.1 Turbo |
| MATH-500 | 90.5 | 91.4 | 0.9 | GPT-5.1 Turbo |
| AIME 2025 | 85.6 | 84.7 | 0.9 | GPT-5.1 |
| LiveCodeBench | 78.9 | 84.6 | 5.7 | GPT-5.1 Turbo |
| IFEval | 90.9 | 93.4 | 2.5 | GPT-5.1 Turbo |
| TruthfulQA | 89.2 | 89.2 | 0.0 | Tie |
| HellaSwag | 92.2 | 91.3 | 0.9 | GPT-5.1 |
| MMMU | 83.3 | 79.7 | 3.6 | GPT-5.1 |
| Arena Elo | 1462.5 | 1482.0 | 19.5 | GPT-5.1 Turbo |
Price analysis
On a blended 3:1 input-to-output basis, GPT-5.1 costs about $31.72 per million tokens and GPT-5.1 Turbo costs about $36.85. GPT-5.1 is roughly 14% cheaper than GPT-5.1 Turbo. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Both models list a 2,000,000-token context window. That is enough for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, GPT-5.1 wins 6, GPT-5.1 Turbo wins 5, and 1 are tied. On the index average, GPT-5.1 Turbo leads GPT-5.1 by 0.1 points (86.1 versus 86.0).
The price picture favours GPT-5.1. The context picture is effectively a tie. 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 GPT-5.1 Turbo for quality-sensitive work and GPT-5.1 for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose GPT-5.1 if
- Unit cost matters and you want the cheaper blended price.
Choose GPT-5.1 Turbo if
- You want the higher average benchmark score in this index.
FAQ
Is GPT-5.1 better than GPT-5.1 Turbo?
On the index average, GPT-5.1 Turbo leads GPT-5.1 by 0.1 points (86.1 versus 86.0). The better choice depends on price, context and your task. GPT-5.1 wins 6 benchmarks, GPT-5.1 Turbo wins 5.
Which is cheaper, GPT-5.1 or GPT-5.1 Turbo?
GPT-5.1 is cheaper on a blended 3:1 basis at about $31.72 per million tokens, versus $36.85 for GPT-5.1 Turbo.
Which has the larger context window?
Both models list a 2,000,000-token context window.
Are these models open weights?
GPT-5.1 is proprietary; GPT-5.1 Turbo is proprietary.
Which should I choose for production?
If you need a single default, start with GPT-5.1 Turbo for quality-sensitive work and GPT-5.1 for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.