Gemini 3 Flash Pro vs o3 Max: which model should you choose?
We compared Gemini 3 Flash Pro and o3 Max on price, context window and 12 benchmarks. Gemini 3 Flash Pro and o3 Max are effectively tied on the index average; Gemini 3 Flash Pro is cheaper on a blended 3:1 basis.
Gemini 3 Flash Pro
Gemini 3 Flash Pro is a frontier model from Google DeepMind. It offers a 400,000-token context window, costs $17.71 per million input tokens and $86.50 per million output tokens, and averages 84.8 across the index's benchmark suite.
- Input
- $17.71 / 1M
- Output
- $86.50 / 1M
- Context
- 400,000
- Avg score
- 84.8
- Open weights
- No
o3 Max
o3 Max is a frontier model from OpenAI. It offers a 2,000,000-token context window, costs $17.82 per million input tokens and $90.55 per million output tokens, and averages 84.8 across the index's benchmark suite.
- Input
- $17.82 / 1M
- Output
- $90.55 / 1M
- Context
- 2,000,000
- Avg score
- 84.8
- Open weights
- No
Specification comparison
| Spec | Gemini 3 Flash Pro | o3 Max | Edge |
|---|---|---|---|
| Input price / 1M | $17.71 | $17.82 | A |
| Output price / 1M | $86.50 | $90.55 | A |
| Context window | 400,000 | 2,000,000 | B |
| Max output | 4,096 | 128,000 | B |
| Average score | 84.8 | 84.8 | Tie |
| Arena Elo | 1469.2 | 1465.2 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Gemini 3 Flash Pro wins 8, o3 Max wins 4, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Gemini 3 Flash Pro | o3 Max | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 87.0 | 84.9 | 2.1 | Gemini 3 Flash Pro |
| GPQA Diamond | 77.7 | 82.7 | 5.0 | o3 Max |
| SWE-bench Verified | 73.3 | 71.8 | 1.5 | Gemini 3 Flash Pro |
| HumanEval | 89.9 | 89.8 | 0.1 | Gemini 3 Flash Pro |
| MATH-500 | 91.8 | 87.0 | 4.8 | Gemini 3 Flash Pro |
| AIME 2025 | 79.9 | 86.2 | 6.3 | o3 Max |
| LiveCodeBench | 80.2 | 76.4 | 3.8 | Gemini 3 Flash Pro |
| IFEval | 92.8 | 92.5 | 0.3 | Gemini 3 Flash Pro |
| TruthfulQA | 86.2 | 87.3 | 1.1 | o3 Max |
| HellaSwag | 90.6 | 93.4 | 2.8 | o3 Max |
| MMMU | 83.0 | 80.8 | 2.2 | Gemini 3 Flash Pro |
| Arena Elo | 1469.2 | 1465.2 | 4.0 | Gemini 3 Flash Pro |
Price analysis
On a blended 3:1 input-to-output basis, Gemini 3 Flash Pro costs about $34.91 per million tokens and o3 Max costs about $36.00. Gemini 3 Flash Pro is roughly 3% cheaper than o3 Max. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
o3 Max has the larger context window at 2,000,000 tokens, compared with 400,000 for Gemini 3 Flash Pro. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Gemini 3 Flash Pro wins 8, o3 Max wins 4, and 0 are tied. The two models are effectively tied on the index average at 84.8.
The price picture favours Gemini 3 Flash Pro. The context picture favours o3 Max. 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 3 Flash Pro if cost is the constraint and o3 Max if context is the constraint. Test both on a sample of your own traffic before committing.
Choose Gemini 3 Flash Pro if
- Unit cost matters and you want the cheaper blended price.
Choose o3 Max if
- You need the larger 2,000,000-token context window.
- You need the larger 128,000-token output limit.
FAQ
Is Gemini 3 Flash Pro better than o3 Max?
The two models are effectively tied on the index average at 84.8. The better choice depends on price, context and your task. Gemini 3 Flash Pro wins 8 benchmarks, o3 Max wins 4.
Which is cheaper, Gemini 3 Flash Pro or o3 Max?
Gemini 3 Flash Pro is cheaper on a blended 3:1 basis at about $34.91 per million tokens, versus $36.00 for o3 Max.
Which has the larger context window?
o3 Max has the larger context window at 2,000,000 tokens. Gemini 3 Flash Pro has 400,000 tokens.
Are these models open weights?
Gemini 3 Flash Pro is proprietary; o3 Max is proprietary.
Which should I choose for production?
If you need a single default, start with Gemini 3 Flash Pro if cost is the constraint and o3 Max if context is the constraint. Test both on a sample of your own traffic before committing.