GPT-5.1 Vision vs o3 Pro: which model should you choose?
We compared GPT-5.1 Vision and o3 Pro on price, context window and 12 benchmarks. o3 Pro has the stronger average benchmark score; GPT-5.1 Vision is cheaper on a blended 3:1 basis.
GPT-5.1 Vision
GPT-5.1 Vision is a frontier model from OpenAI. It offers a 400,000-token context window, costs $17.76 per million input tokens and $80.59 per million output tokens, and averages 84.8 across the index's benchmark suite.
- Input
- $17.76 / 1M
- Output
- $80.59 / 1M
- Context
- 400,000
- Avg score
- 84.8
- Open weights
- No
o3 Pro
o3 Pro is a frontier model from OpenAI. It offers a 400,000-token context window, costs $17.89 per million input tokens and $81.48 per million output tokens, and averages 85.8 across the index's benchmark suite.
- Input
- $17.89 / 1M
- Output
- $81.48 / 1M
- Context
- 400,000
- Avg score
- 85.8
- Open weights
- No
Specification comparison
| Spec | GPT-5.1 Vision | o3 Pro | Edge |
|---|---|---|---|
| Input price / 1M | $17.76 | $17.89 | A |
| Output price / 1M | $80.59 | $81.48 | A |
| Context window | 400,000 | 400,000 | Tie |
| Max output | 16,384 | 8,192 | A |
| Average score | 84.8 | 85.8 | B |
| Arena Elo | 1462.4 | 1471.9 | B |
| Open weights | No | No | Tie |
Benchmark comparison
GPT-5.1 Vision wins 3, o3 Pro wins 8, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | GPT-5.1 Vision | o3 Pro | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 85.5 | 84.3 | 1.2 | GPT-5.1 Vision |
| GPQA Diamond | 78.7 | 78.7 | 0.0 | Tie |
| SWE-bench Verified | 73.6 | 76.9 | 3.3 | o3 Pro |
| HumanEval | 89.6 | 90.6 | 1.0 | o3 Pro |
| MATH-500 | 89.1 | 92.4 | 3.3 | o3 Pro |
| AIME 2025 | 82.4 | 83.5 | 1.1 | o3 Pro |
| LiveCodeBench | 77.8 | 82.4 | 4.6 | o3 Pro |
| IFEval | 92.7 | 90.9 | 1.8 | GPT-5.1 Vision |
| TruthfulQA | 86.9 | 88.4 | 1.5 | o3 Pro |
| HellaSwag | 92.1 | 92.5 | 0.4 | o3 Pro |
| MMMU | 83.9 | 83.1 | 0.8 | GPT-5.1 Vision |
| Arena Elo | 1462.4 | 1471.9 | 9.5 | o3 Pro |
Price analysis
On a blended 3:1 input-to-output basis, GPT-5.1 Vision costs about $33.47 per million tokens and o3 Pro costs about $33.79. GPT-5.1 Vision is roughly 1% cheaper than o3 Pro. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Both models list a 400,000-token context window. That is enough for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, GPT-5.1 Vision wins 3, o3 Pro wins 8, and 1 are tied. On the index average, o3 Pro leads GPT-5.1 Vision by 1.0 points (85.8 versus 84.8).
The price picture favours GPT-5.1 Vision. 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 o3 Pro for quality-sensitive work and GPT-5.1 Vision for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose GPT-5.1 Vision if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 16,384-token output limit.
Choose o3 Pro if
- You want the higher average benchmark score in this index.
FAQ
Is GPT-5.1 Vision better than o3 Pro?
On the index average, o3 Pro leads GPT-5.1 Vision by 1.0 points (85.8 versus 84.8). The better choice depends on price, context and your task. GPT-5.1 Vision wins 3 benchmarks, o3 Pro wins 8.
Which is cheaper, GPT-5.1 Vision or o3 Pro?
GPT-5.1 Vision is cheaper on a blended 3:1 basis at about $33.47 per million tokens, versus $33.79 for o3 Pro.
Which has the larger context window?
Both models list a 400,000-token context window.
Are these models open weights?
GPT-5.1 Vision is proprietary; o3 Pro is proprietary.
Which should I choose for production?
If you need a single default, start with o3 Pro for quality-sensitive work and GPT-5.1 Vision for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.