Gemini 3 Flash Pro vs Gemini 3 Flash Reasoning: which model should you choose?
We compared Gemini 3 Flash Pro and Gemini 3 Flash Reasoning on price, context window and 12 benchmarks. Gemini 3 Flash Pro has the stronger average benchmark score; Gemini 3 Flash Reasoning 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
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 3 Flash Pro | Gemini 3 Flash Reasoning | Edge |
|---|---|---|---|
| Input price / 1M | $17.71 | $17.05 | B |
| Output price / 1M | $86.50 | $66.77 | B |
| Context window | 400,000 | 128,000 | A |
| Max output | 4,096 | 32,768 | B |
| Average score | 84.8 | 83.7 | A |
| Arena Elo | 1469.2 | 1446.9 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Gemini 3 Flash Pro 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 3 Flash Pro | Gemini 3 Flash Reasoning | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 87.0 | 87.2 | 0.2 | Gemini 3 Flash Reasoning |
| GPQA Diamond | 77.7 | 81.8 | 4.1 | Gemini 3 Flash Reasoning |
| SWE-bench Verified | 73.3 | 72.5 | 0.8 | Gemini 3 Flash Pro |
| HumanEval | 89.9 | 86.9 | 3.0 | Gemini 3 Flash Pro |
| MATH-500 | 91.8 | 86.2 | 5.6 | Gemini 3 Flash Pro |
| AIME 2025 | 79.9 | 79.4 | 0.5 | Gemini 3 Flash Pro |
| LiveCodeBench | 80.2 | 77.7 | 2.5 | Gemini 3 Flash Pro |
| IFEval | 92.8 | 90.2 | 2.6 | Gemini 3 Flash Pro |
| TruthfulQA | 86.2 | 86.6 | 0.4 | Gemini 3 Flash Reasoning |
| HellaSwag | 90.6 | 92.2 | 1.6 | Gemini 3 Flash Reasoning |
| MMMU | 83.0 | 79.8 | 3.2 | Gemini 3 Flash Pro |
| Arena Elo | 1469.2 | 1446.9 | 22.3 | 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 Gemini 3 Flash Reasoning costs about $29.48. Gemini 3 Flash Reasoning is roughly 16% cheaper than Gemini 3 Flash Pro. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Gemini 3 Flash Pro has the larger context window at 400,000 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 3 Flash Pro wins 8, Gemini 3 Flash Reasoning wins 4, and 0 are tied. On the index average, Gemini 3 Flash Pro leads Gemini 3 Flash Reasoning by 1.1 points (84.8 versus 83.7).
The price picture favours Gemini 3 Flash Reasoning. The context picture favours Gemini 3 Flash Pro. 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 for quality-sensitive work and Gemini 3 Flash Reasoning for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.
Choose Gemini 3 Flash Pro if
- You want the higher average benchmark score in this index.
- You need the larger 400,000-token context window.
Choose Gemini 3 Flash Reasoning if
- Unit cost matters and you want the cheaper blended price.
- You need the larger 32,768-token output limit.
FAQ
Is Gemini 3 Flash Pro better than Gemini 3 Flash Reasoning?
On the index average, Gemini 3 Flash Pro 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 3 Flash Pro wins 8 benchmarks, Gemini 3 Flash Reasoning wins 4.
Which is cheaper, Gemini 3 Flash Pro or Gemini 3 Flash Reasoning?
Gemini 3 Flash Reasoning is cheaper on a blended 3:1 basis at about $29.48 per million tokens, versus $34.91 for Gemini 3 Flash Pro.
Which has the larger context window?
Gemini 3 Flash Pro has the larger context window at 400,000 tokens. Gemini 3 Flash Reasoning has 128,000 tokens.
Are these models open weights?
Gemini 3 Flash Pro is proprietary; Gemini 3 Flash Reasoning is proprietary.
Which should I choose for production?
If you need a single default, start with Gemini 3 Flash Pro for quality-sensitive work and Gemini 3 Flash Reasoning for high-volume, well-scoped tasks. Run both on a sample of your own traffic before locking in a choice.