GPT-5.2 Vision vs o3 Reasoning: which model should you choose?
We compared GPT-5.2 Vision and o3 Reasoning on price, context window and 12 benchmarks. GPT-5.2 Vision has the stronger average benchmark score; o3 Reasoning is cheaper on a blended 3:1 basis.
GPT-5.2 Vision
GPT-5.2 Vision is a frontier model from OpenAI. It offers a 1,000,000-token context window, costs $19.03 per million input tokens and $85.72 per million output tokens, and averages 87.4 across the index's benchmark suite.
- Input
- $19.03 / 1M
- Output
- $85.72 / 1M
- Context
- 1,000,000
- Avg score
- 87.4
- Open weights
- No
o3 Reasoning
o3 Reasoning is a frontier model from OpenAI. It offers a 200,000-token context window, costs $18.07 per million input tokens and $70.65 per million output tokens, and averages 85.3 across the index's benchmark suite.
- Input
- $18.07 / 1M
- Output
- $70.65 / 1M
- Context
- 200,000
- Avg score
- 85.3
- Open weights
- No
Specification comparison
| Spec | GPT-5.2 Vision | o3 Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $19.03 | $18.07 | B |
| Output price / 1M | $85.72 | $70.65 | B |
| Context window | 1,000,000 | 200,000 | A |
| Max output | 16,384 | 16,384 | Tie |
| Average score | 87.4 | 85.3 | A |
| Arena Elo | 1484.3 | 1456.9 | A |
| Open weights | No | No | Tie |
Benchmark comparison
GPT-5.2 Vision wins 10, o3 Reasoning wins 2, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | GPT-5.2 Vision | o3 Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 89.5 | 87.7 | 1.8 | GPT-5.2 Vision |
| GPQA Diamond | 82.1 | 79.6 | 2.5 | GPT-5.2 Vision |
| SWE-bench Verified | 78.8 | 74.1 | 4.7 | GPT-5.2 Vision |
| HumanEval | 91.2 | 91.3 | 0.1 | o3 Reasoning |
| MATH-500 | 92.9 | 92.0 | 0.9 | GPT-5.2 Vision |
| AIME 2025 | 85.7 | 80.5 | 5.2 | GPT-5.2 Vision |
| LiveCodeBench | 83.4 | 82.7 | 0.7 | GPT-5.2 Vision |
| IFEval | 93.9 | 90.6 | 3.3 | GPT-5.2 Vision |
| TruthfulQA | 85.3 | 86.5 | 1.2 | o3 Reasoning |
| HellaSwag | 94.6 | 90.9 | 3.7 | GPT-5.2 Vision |
| MMMU | 84.4 | 82.3 | 2.1 | GPT-5.2 Vision |
| Arena Elo | 1484.3 | 1456.9 | 27.4 | GPT-5.2 Vision |
Price analysis
On a blended 3:1 input-to-output basis, GPT-5.2 Vision costs about $35.70 per million tokens and o3 Reasoning costs about $31.22. o3 Reasoning is roughly 13% cheaper than GPT-5.2 Vision. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
GPT-5.2 Vision has the larger context window at 1,000,000 tokens, compared with 200,000 for o3 Reasoning. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, GPT-5.2 Vision wins 10, o3 Reasoning wins 2, and 0 are tied. On the index average, GPT-5.2 Vision leads o3 Reasoning by 2.1 points (87.4 versus 85.3).
The price picture favours o3 Reasoning. The context picture favours GPT-5.2 Vision. 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-5.2 Vision for quality-sensitive work and o3 Reasoning for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose GPT-5.2 Vision if
- You want the higher average benchmark score in this index.
- You need the larger 1,000,000-token context window.
Choose o3 Reasoning if
- Unit cost matters and you want the cheaper blended price.
FAQ
Is GPT-5.2 Vision better than o3 Reasoning?
On the index average, GPT-5.2 Vision leads o3 Reasoning by 2.1 points (87.4 versus 85.3). The better choice depends on price, context and your task. GPT-5.2 Vision wins 10 benchmarks, o3 Reasoning wins 2.
Which is cheaper, GPT-5.2 Vision or o3 Reasoning?
o3 Reasoning is cheaper on a blended 3:1 basis at about $31.22 per million tokens, versus $35.70 for GPT-5.2 Vision.
Which has the larger context window?
GPT-5.2 Vision has the larger context window at 1,000,000 tokens. o3 Reasoning has 200,000 tokens.
Are these models open weights?
GPT-5.2 Vision is proprietary; o3 Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with GPT-5.2 Vision for quality-sensitive work and o3 Reasoning for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.