Gemini 2.5 Pro Max vs Gemini 3 Flash Reasoning: which model should you choose?
We compared Gemini 2.5 Pro Max and Gemini 3 Flash Reasoning on price, context window and 12 benchmarks. Gemini 2.5 Pro Max has the stronger average benchmark score; Gemini 2.5 Pro Max is cheaper on a blended 3:1 basis.
Gemini 2.5 Pro Max
Gemini 2.5 Pro Max is a frontier model from Google DeepMind. It offers a 200,000-token context window, costs $16.94 per million input tokens and $64.80 per million output tokens, and averages 84.8 across the index's benchmark suite.
- Input
- $16.94 / 1M
- Output
- $64.80 / 1M
- Context
- 200,000
- Avg score
- 84.8
- Open weights
- No
Gemini 3 Flash Reasoning
Gemini 3 Flash Reasoning is a frontier model from Google DeepMind. It offers a 128,000-token context window, costs $17.05 per million input tokens and $66.77 per million output tokens, and averages 83.7 across the index's benchmark suite.
- Input
- $17.05 / 1M
- Output
- $66.77 / 1M
- Context
- 128,000
- Avg score
- 83.7
- Open weights
- No
Specification comparison
| Spec | Gemini 2.5 Pro Max | Gemini 3 Flash Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $16.94 | $17.05 | A |
| Output price / 1M | $64.80 | $66.77 | A |
| Context window | 200,000 | 128,000 | A |
| Max output | 65,536 | 32,768 | A |
| Average score | 84.8 | 83.7 | A |
| Arena Elo | 1450.2 | 1446.9 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Gemini 2.5 Pro Max wins 8, Gemini 3 Flash Reasoning wins 4, and 0 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Gemini 2.5 Pro Max | Gemini 3 Flash Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 86.7 | 87.2 | 0.5 | Gemini 3 Flash Reasoning |
| GPQA Diamond | 79.8 | 81.8 | 2.0 | Gemini 3 Flash Reasoning |
| SWE-bench Verified | 75.5 | 72.5 | 3.0 | Gemini 2.5 Pro Max |
| HumanEval | 87.0 | 86.9 | 0.1 | Gemini 2.5 Pro Max |
| MATH-500 | 91.6 | 86.2 | 5.4 | Gemini 2.5 Pro Max |
| AIME 2025 | 82.6 | 79.4 | 3.2 | Gemini 2.5 Pro Max |
| LiveCodeBench | 79.9 | 77.7 | 2.2 | Gemini 2.5 Pro Max |
| IFEval | 91.3 | 90.2 | 1.1 | Gemini 2.5 Pro Max |
| TruthfulQA | 85.5 | 86.6 | 1.1 | Gemini 3 Flash Reasoning |
| HellaSwag | 92.9 | 92.2 | 0.7 | Gemini 2.5 Pro Max |
| MMMU | 79.7 | 79.8 | 0.1 | Gemini 3 Flash Reasoning |
| Arena Elo | 1450.2 | 1446.9 | 3.3 | Gemini 2.5 Pro Max |
Price analysis
On a blended 3:1 input-to-output basis, Gemini 2.5 Pro Max costs about $28.91 per million tokens and Gemini 3 Flash Reasoning costs about $29.48. Gemini 2.5 Pro Max is roughly 2% cheaper than Gemini 3 Flash Reasoning. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Gemini 2.5 Pro Max has the larger context window at 200,000 tokens, compared with 128,000 for Gemini 3 Flash Reasoning. That matters for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Gemini 2.5 Pro Max wins 8, Gemini 3 Flash Reasoning wins 4, and 0 are tied. On the index average, Gemini 2.5 Pro Max leads Gemini 3 Flash Reasoning by 1.1 points (84.8 versus 83.7).
The price picture favours Gemini 2.5 Pro Max. The context picture favours Gemini 2.5 Pro 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 2.5 Pro Max for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Gemini 2.5 Pro Max if
- You want the higher average benchmark score in this index.
- Unit cost matters and you want the cheaper blended price.
- You need the larger 200,000-token context window.
- You need the larger 65,536-token output limit.
Choose Gemini 3 Flash Reasoning if
- You prefer Google DeepMind's tooling or already use it.
FAQ
Is Gemini 2.5 Pro Max better than Gemini 3 Flash Reasoning?
On the index average, Gemini 2.5 Pro Max leads Gemini 3 Flash Reasoning by 1.1 points (84.8 versus 83.7). The better choice depends on price, context and your task. Gemini 2.5 Pro Max wins 8 benchmarks, Gemini 3 Flash Reasoning wins 4.
Which is cheaper, Gemini 2.5 Pro Max or Gemini 3 Flash Reasoning?
Gemini 2.5 Pro Max is cheaper on a blended 3:1 basis at about $28.91 per million tokens, versus $29.48 for Gemini 3 Flash Reasoning.
Which has the larger context window?
Gemini 2.5 Pro Max has the larger context window at 200,000 tokens. Gemini 3 Flash Reasoning has 128,000 tokens.
Are these models open weights?
Gemini 2.5 Pro Max is proprietary; Gemini 3 Flash Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with Gemini 2.5 Pro Max for quality-sensitive work, and check whether its price holds at your expected volume before committing.