Model Comparison
Gemini 3 Flash vs Grok-4.20 Beta ReasoningWhich is better in 2026?
Gemini 3 Flash significantly outperforms across most benchmarks. Gemini 3 Flash is 2.7x cheaper per token.
Verdict: Gemini 3 Flash vs Grok-4.20 Beta Reasoning — which is better?
Gemini 3 Flash (by Google) and Grok-4.20 Beta Reasoning (by xAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
Gemini 3 Flash outperforms in 1 benchmarks (Finance Agent v2), while Grok-4.20 Beta Reasoning is better at 0 benchmarks. Gemini 3 Flash significantly outperforms across most benchmarks.
On price, Gemini 3 Flash is roughly 2.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Grok-4.20 Beta Reasoning also accepts a larger context window (2,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Gemini 3 Flash if…
- you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
- cost matters — it's about 2.7x cheaper per token
Choose Grok-4.20 Beta Reasoning if…
- you process long inputs — it offers a 2,000,000 token context window
- you want the most recent training data — it shipped Mar 2026
Performance Benchmarks
Comparative analysis across standard metrics
Gemini 3 Flash outperforms in 1 benchmarks (Finance Agent v2), while Grok-4.20 Beta Reasoning is better at 0 benchmarks.
Gemini 3 Flash significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Gemini 3 Flash ($0.50/1M tokens) is 4.0x cheaper than Grok-4.20 Beta Reasoning ($2.00/1M tokens).
For output processing, Gemini 3 Flash ($3.00/1M tokens) is 2.0x cheaper than Grok-4.20 Beta Reasoning ($6.00/1M tokens).
In conclusion, Grok-4.20 Beta Reasoning is more expensive than Gemini 3 Flash.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Grok-4.20 Beta Reasoning accepts 2,000,000 input tokens compared to Gemini 3 Flash's 1,000,000 tokens. Gemini 3 Flash can generate longer responses up to 65,536 tokens, while Grok-4.20 Beta Reasoning is limited to 30,000 tokens.
Input Capabilities
Supported data types and modalities
Both Gemini 3 Flash and Grok-4.20 Beta Reasoning support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Gemini 3 Flash
Grok-4.20 Beta Reasoning
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Gemini 3 Flash was released on 2025-12-17, while Grok-4.20 Beta Reasoning was released on 2026-03-09.
Grok-4.20 Beta Reasoning is 3 months newer than Gemini 3 Flash.
Dec 17, 2025
6 months ago
Mar 9, 2026
3 months ago
2mo newerKnowledge Cutoff
When training data ends
Gemini 3 Flash has a documented knowledge cutoff of 2025-01-31, while Grok-4.20 Beta Reasoning's cutoff date is not specified.
We can confirm Gemini 3 Flash's training data extends to 2025-01-31, but cannot make a direct comparison without Grok-4.20 Beta Reasoning's cutoff date.
Jan 2025
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Provider Availability
Gemini 3 Flash is available from Google. Grok-4.20 Beta Reasoning is available from xAI.
Gemini 3 Flash
Grok-4.20 Beta Reasoning
Outputs Comparison
Key Takeaways
Detailed Comparison
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FAQ
Common questions about Gemini 3 Flash vs Grok-4.20 Beta Reasoning.