GPT-5.1: pricing, context window and benchmarks
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.
Pricing
GPT-5.1 costs $19.01 per million input tokens and $69.84 per million output tokens. A blended 3:1 input-to-output mix works out to about $31.72 per million tokens. Cached input is listed at $1.77 per million tokens.
| Item | Price | Notes |
|---|---|---|
| Input | $19.01 | per 1M tokens |
| Output | $69.84 | per 1M tokens |
| Cached input | $1.77 | per 1M tokens |
| Blended 3:1 | $31.72 | estimate per 1M tokens |
| 1M in + 1M out | $88.85 | estimate |
Benchmarks
Scores below are modelled estimates on a 0–100 scale. Use them to compare relative position, not as official vendor results.
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 86.1 | 51 | 92th | |
| GPQA Diamond | 82.3 | 25 | 96th | |
| SWE-bench Verified | 76.1 | 29 | 95th | |
| HumanEval | 90.6 | 36 | 94th | |
| MATH-500 | 90.5 | 43 | 93th | |
| AIME 2025 | 85.6 | 29 | 95th | |
| LiveCodeBench | 78.9 | 55 | 91th | |
| IFEval | 90.9 | 56 | 91th | |
| TruthfulQA | 89.2 | 9 | 99th | |
| HellaSwag | 92.2 | 39 | 94th | |
| MMMU | 83.3 | 17 | 97th | |
| Arena Elo | 1462.5 | 46 | 92th |
What GPT-5.1 is good for
GPT-5.1 sits in the frontier tier of the index. It is aimed at work where answer quality matters more than unit cost: hard reasoning, multi-step coding, document analysis and multimodal inputs. At $19.01 per million input tokens and a 2,000,000-token context window, it is a premium option, so reserve it for tasks where a cheaper model measurably fails.
Strengths
- Top-tier average benchmark score (86.0), placing it #33 of 600.
- Large 2,000,000-token context window for long documents and agent traces.
- Accepts more than text, including image input where the provider supports it.
- Reasoning-oriented profile, useful for multi-step problems and structured analysis.
- Coding benchmarks are a relative strength within its tier.
Trade-offs
- Proprietary licence: you cannot download the weights or self-host the model.
- Premium input pricing at $19.01 per million tokens.
- Cost can climb quickly on long outputs and high-volume traffic.
How it compares
| Model | Provider | Context | Input / 1M | Avg score |
|---|---|---|---|---|
| GPT-5.1 Turbo | OpenAI | 2000000 | $19.19 | 86.1 |
| Gemini 3 Pro | Google DeepMind | 2000000 | $18.24 | 86.1 |
| Claude Sonnet 4.5 | Anthropic | 400000 | $17.84 | 86.0 |
| GPT-5.1 | OpenAI | 2000000 | $19.01 | 86.0 |
| Grok 3 Max | xAI | 2000000 | $17.66 | 85.9 |
| Qwen3-Max Max | Alibaba Cloud | 400000 | $18.53 | 85.9 |
FAQ
How much does GPT-5.1 cost?
GPT-5.1 is listed at $19.01 per million input tokens and $69.84 per million output tokens. Cached input is $1.77 per million tokens. A blended 3:1 input-to-output mix is about $31.72 per million tokens.
What is the context window of GPT-5.1?
GPT-5.1 has a context window of 2,000,000 tokens and can emit up to 128,000 output tokens per request in this index.
Is GPT-5.1 open weights?
No. GPT-5.1 is a proprietary model with a proprietary licence, so you cannot download the weights.
How does GPT-5.1 score on benchmarks?
GPT-5.1 averages 86.0 across the scored benchmarks in this index, ranking #33 of 600 models. Its strongest relative result is TruthfulQA at 89.2.
What is GPT-5.1 best for?
GPT-5.1 sits in the frontier tier of the index. It is aimed at work where answer quality matters more than unit cost: hard reasoning, multi-step coding, document analysis and multimodal inputs. At $19.01 per million input tokens and a 2,000,000-token context window, it is a premium option, so reserve it for tasks where a cheaper model measurably fails.