Gemini 3 Flash vs Grok 3: which model should you choose?
We compared Gemini 3 Flash and Grok 3 on price, context window and 12 benchmarks. Gemini 3 Flash has the stronger average benchmark score; Gemini 3 Flash is cheaper on a blended 3:1 basis.
Gemini 3 Flash
Gemini 3 Flash is a multimodal model from Google DeepMind. It offers a 128,000-token context window, costs $15.67 per million input tokens and $70.15 per million output tokens, and averages 83.6 across the index's benchmark suite.
- Input
- $15.67 / 1M
- Output
- $70.15 / 1M
- Context
- 128,000
- Avg score
- 83.6
- Open weights
- No
Grok 3
Grok 3 is a multimodal model from xAI. It offers a 128,000-token context window, costs $15.84 per million input tokens and $70.31 per million output tokens, and averages 82.8 across the index's benchmark suite.
- Input
- $15.84 / 1M
- Output
- $70.31 / 1M
- Context
- 128,000
- Avg score
- 82.8
- Open weights
- No
Specification comparison
| Spec | Gemini 3 Flash | Grok 3 | Edge |
|---|---|---|---|
| Input price / 1M | $15.67 | $15.84 | A |
| Output price / 1M | $70.15 | $70.31 | A |
| Context window | 128,000 | 128,000 | Tie |
| Max output | 65,536 | 4,096 | A |
| Average score | 83.6 | 82.8 | A |
| Arena Elo | 1450.7 | 1447.2 | A |
| Open weights | No | No | Tie |
Benchmark comparison
Gemini 3 Flash wins 7, Grok 3 wins 4, and 1 benchmarks are tied. The table shows the modelled score for each model and the gap.
| Benchmark | Gemini 3 Flash | Grok 3 | Gap | Winner |
|---|---|---|---|---|
| MMLU-Pro | 83.7 | 81.9 | 1.8 | Gemini 3 Flash |
| GPQA Diamond | 80.3 | 80.0 | 0.3 | Gemini 3 Flash |
| SWE-bench Verified | 72.5 | 72.6 | 0.1 | Grok 3 |
| HumanEval | 86.2 | 85.3 | 0.9 | Gemini 3 Flash |
| MATH-500 | 89.0 | 88.7 | 0.3 | Gemini 3 Flash |
| AIME 2025 | 84.5 | 81.1 | 3.4 | Gemini 3 Flash |
| LiveCodeBench | 79.3 | 74.3 | 5.0 | Gemini 3 Flash |
| IFEval | 91.0 | 91.0 | 0.0 | Tie |
| TruthfulQA | 84.8 | 85.4 | 0.6 | Grok 3 |
| HellaSwag | 89.8 | 91.4 | 1.6 | Grok 3 |
| MMMU | 78.2 | 79.1 | 0.9 | Grok 3 |
| Arena Elo | 1450.7 | 1447.2 | 3.5 | Gemini 3 Flash |
Price analysis
On a blended 3:1 input-to-output basis, Gemini 3 Flash costs about $29.29 per million tokens and Grok 3 costs about $29.46. Gemini 3 Flash is roughly 1% cheaper than Grok 3. At high volume, that gap compounds quickly, so price should carry real weight unless the quality difference is decisive.
Both models list a 128,000-token context window. That is enough for long documents, large codebases and multi-step agent traces.
Verdict
Across 12 shared benchmarks, Gemini 3 Flash wins 7, Grok 3 wins 4, and 1 are tied. On the index average, Gemini 3 Flash leads Grok 3 by 0.8 points (83.6 versus 82.8).
The price picture favours Gemini 3 Flash. The context picture is effectively a tie. 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 for quality-sensitive work, and check whether its price holds at your expected volume before committing.
Choose Gemini 3 Flash 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 65,536-token output limit.
Choose Grok 3 if
- You prefer xAI's tooling or already use it.
FAQ
Is Gemini 3 Flash better than Grok 3?
On the index average, Gemini 3 Flash leads Grok 3 by 0.8 points (83.6 versus 82.8). The better choice depends on price, context and your task. Gemini 3 Flash wins 7 benchmarks, Grok 3 wins 4.
Which is cheaper, Gemini 3 Flash or Grok 3?
Gemini 3 Flash is cheaper on a blended 3:1 basis at about $29.29 per million tokens, versus $29.46 for Grok 3.
Which has the larger context window?
Both models list a 128,000-token context window.
Are these models open weights?
Gemini 3 Flash is proprietary; Grok 3 is proprietary.
Which should I choose for production?
If you need a single default, start with Gemini 3 Flash for quality-sensitive work, and check whether its price holds at your expected volume before committing.