Gemini 2.5 Pro Reasoning vs o3 Turbo: which model should you choose?
We compared Gemini 2.5 Pro Reasoning and o3 Turbo on price, context window and 12 benchmarks. Gemini 2.5 Pro Reasoning has the stronger average benchmark score; Gemini 2.5 Pro Reasoning is cheaper on a blended 3:1 basis.
Gemini 2.5 Pro Reasoning
Gemini 2.5 Pro Reasoning is a frontier model from Google DeepMind. It offers a 128,000-token context window, costs $16.81 per million input tokens and $67.95 per million output tokens, and averages 83.8 across the index's benchmark suite.
- Input
- $16.81 / 1M
- Output
- $67.95 / 1M
- Context
- 128,000
- Avg score
- 83.8
- Open weights
- No
o3 Turbo
o3 Turbo is a frontier model from OpenAI. It offers a 200,000-token context window, costs $16.63 per million input tokens and $83.71 per million output tokens, and averages 83.4 across the index's benchmark suite.
- Input
- $16.63 / 1M
- Output
- $83.71 / 1M
- Context
- 200,000
- Avg score
- 83.4
- Open weights
- No
Specification comparison
| Spec | Gemini 2.5 Pro Reasoning | o3 Turbo | Edge |
|---|---|---|---|
| Input price / 1M | $16.81 | $16.63 | B |
| Output price / 1M | $67.95 | $83.71 | A |
| Context window | 128,000 | 200,000 | B |
| Max output | 4,096 | 4,096 | Tie |
| Average score | 83.8 | 83.4 | A |
| Arena Elo | 1472.1 | 1456.2 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Gemini 2.5 Pro Reasoning wins 9, o3 Turbo wins 3, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Gemini 2.5 Pro Reasoning | o3 Turbo | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 86.8 | 82.7 | 4.1 | Gemini 2.5 Pro Reasoning |
| GPQA Diamond | 80.0 | 77.7 | 2.3 | Gemini 2.5 Pro Reasoning |
| SWE-bench Verified | 71.2 | 70.7 | 0.5 | Gemini 2.5 Pro Reasoning |
| HumanEval | 86.7 | 87.4 | 0.7 | o3 Turbo |
| MATH-500 | 87.9 | 90.6 | 2.7 | o3 Turbo |
| AIME 2025 | 84.2 | 83.0 | 1.2 | Gemini 2.5 Pro Reasoning |
| LiveCodeBench | 74.8 | 80.7 | 5.9 | o3 Turbo |
| IFEval | 90.8 | 89.1 | 1.7 | Gemini 2.5 Pro Reasoning |
| TruthfulQA | 84.0 | 83.6 | 0.4 | Gemini 2.5 Pro Reasoning |
| HellaSwag | 92.1 | 91.8 | 0.3 | Gemini 2.5 Pro Reasoning |
| MMMU | 82.8 | 79.7 | 3.1 | Gemini 2.5 Pro Reasoning |
| Arena Elo | 1472.1 | 1456.2 | 15.9 | Gemini 2.5 Pro Reasoning |
Price analysis
On a blended 3:1 input-to-output basis, Gemini 2.5 Pro Reasoning costs about $29.59 per million tokens and o3 Turbo costs about $33.40. Gemini 2.5 Pro Reasoning is roughly 11% cheaper than o3 Turbo. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
o3 Turbo has the larger context window at 200,000 tokens, compared with 128,000 for Gemini 2.5 Pro Reasoning. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Gemini 2.5 Pro Reasoning wins 9, o3 Turbo wins 3, and 0 are tied. On the index average, Gemini 2.5 Pro Reasoning leads o3 Turbo by 0.4 points (83.8 versus 83.4).
The price picture favours Gemini 2.5 Pro Reasoning. The context picture favours o3 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 2.5 Pro Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Gemini 2.5 Pro Reasoning if
- You want the higher average benchmark score in this index.
- Unit cost matters and you want the cheaper blended price.
Choose o3 Turbo if
- You need the larger 200,000-token context window.
FAQ
Is Gemini 2.5 Pro Reasoning better than o3 Turbo?
On the index average, Gemini 2.5 Pro Reasoning leads o3 Turbo by 0.4 points (83.8 versus 83.4). The better choice depends on price, context and your task. Gemini 2.5 Pro Reasoning wins 9 benchmarks, o3 Turbo wins 3.
Which is cheaper, Gemini 2.5 Pro Reasoning or o3 Turbo?
Gemini 2.5 Pro Reasoning is cheaper on a blended 3:1 basis at about $29.59 per million tokens, versus $33.40 for o3 Turbo.
Which has the larger context window?
o3 Turbo has the larger context window at 200,000 tokens. Gemini 2.5 Pro Reasoning has 128,000 tokens.
Are these models open weights?
Gemini 2.5 Pro Reasoning is proprietary; o3 Turbo is proprietary.
Which should I choose for production?
If you need a single default, start with Gemini 2.5 Pro Reasoning for quality-sensitive work, and check whether its price holds at your expected volume before committing.