Model Comparison

Gemini 3 Flash vs Grok 4 FastWhich is better in 2026?

Gemini 3 Flash shows notably better performance in the majority of benchmarks. Grok 4 Fast is 4.1x cheaper per token.

Verdict: Gemini 3 Flash vs Grok 4 Fast — which is better?

Gemini 3 Flash (by Google) and Grok 4 Fast (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 3 benchmarks (AIME 2025, GPQA, Humanity's Last Exam), while Grok 4 Fast is better at 1 benchmark (SimpleQA). Gemini 3 Flash shows notably better performance in the majority of benchmarks.

On price, Grok 4 Fast is roughly 4.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Grok 4 Fast 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 3 of 4 shared benchmarks
  • you want the most recent training data — it shipped Dec 2025

Choose Grok 4 Fast if…

  • cost matters — it's about 4.1x cheaper per token
  • you process long inputs — it offers a 2,000,000 token context window
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Performance Benchmarks

Comparative analysis across standard metrics

4 benchmarks

Gemini 3 Flash outperforms in 3 benchmarks (AIME 2025, GPQA, Humanity's Last Exam), while Grok 4 Fast is better at 1 benchmark (SimpleQA).

Gemini 3 Flash shows notably better performance in the majority of benchmarks.

Mon Jun 08 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Grok 4 Fast costs less

For input processing, Gemini 3 Flash ($0.50/1M tokens) is 2.5x more expensive than Grok 4 Fast ($0.20/1M tokens).

For output processing, Gemini 3 Flash ($3.00/1M tokens) is 6.0x more expensive than Grok 4 Fast ($0.50/1M tokens).

In conclusion, Gemini 3 Flash is more expensive than Grok 4 Fast.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Mon Jun 08 2026 • llm-stats.com
Google
Gemini 3 Flash
Input tokens$0.50
Output tokens$3.00
Best providerGoogle
xAI
Grok 4 Fast
Input tokens$0.20
Output tokens$0.50
Best providerxAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Grok 4 Fast 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 Fast is limited to 30,000 tokens.

Google
Gemini 3 Flash
Input1,000,000 tokens
Output65,536 tokens
xAI
Grok 4 Fast
Input2,000,000 tokens
Output30,000 tokens
Mon Jun 08 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 3 Flash and Grok 4 Fast support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Gemini 3 Flash

Text
Images
Audio
Video

Grok 4 Fast

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Gemini 3 Flash

Proprietary

Closed source

Grok 4 Fast

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 3 Flash was released on 2025-12-17, while Grok 4 Fast was released on 2025-08-28.

Gemini 3 Flash is 4 months newer than Grok 4 Fast.

Gemini 3 Flash

Dec 17, 2025

5 months ago

3mo newer
Grok 4 Fast

Aug 28, 2025

9 months ago

Knowledge Cutoff

When training data ends

Gemini 3 Flash has a documented knowledge cutoff of 2025-01-31, while Grok 4 Fast'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 Fast's cutoff date.

Gemini 3 Flash

Jan 2025

Grok 4 Fast

—

Provider Availability

Gemini 3 Flash is available from Google. Grok 4 Fast is available from xAI.

Gemini 3 Flash

google logo
Google
Input Price:Input: $0.50/1MOutput Price:Output: $3.00/1M

Grok 4 Fast

xai logo
xAI
Input Price:Input: $0.20/1MOutput Price:Output: $0.50/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Google
Higher AIME 2025 score (99.7% vs 92.0%)
Higher GPQA score (90.4% vs 85.7%)
Higher Humanity's Last Exam score (43.5% vs 20.0%)
xAI
Larger context window (2,000,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher SimpleQA score (95.0% vs 68.7%)

Detailed Comparison

AI Model Comparison Table
Feature
Google
Gemini 3 Flash
xAI
Grok 4 Fast

FAQ

Common questions about Gemini 3 Flash vs Grok 4 Fast.

Which is better, Gemini 3 Flash or Grok 4 Fast?

Gemini 3 Flash shows notably better performance in the majority of benchmarks. Gemini 3 Flash is made by Google and Grok 4 Fast is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Gemini 3 Flash compare to Grok 4 Fast in benchmarks?

Gemini 3 Flash scores Vending-Bench 2: 100.0%, AIME 2025: 99.7%, Global PIQA: 92.8%, MMMLU: 91.8%, GPQA: 90.4%. Grok 4 Fast scores SimpleQA: 95.0%, HMMT 2025: 93.3%, AIME 2025: 92.0%, GPQA: 85.7%, LiveCodeBench: 80.0%.

Is Gemini 3 Flash cheaper than Grok 4 Fast?

Grok 4 Fast is 2.5x cheaper for input tokens. Gemini 3 Flash costs $0.50/M input and $3.00/M output via google. Grok 4 Fast costs $0.20/M input and $0.50/M output via xai.

What are the context window sizes for Gemini 3 Flash and Grok 4 Fast?

Gemini 3 Flash supports 1.0M tokens and Grok 4 Fast supports 2.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Gemini 3 Flash and Grok 4 Fast?

Key differences include context window (1.0M vs 2.0M), input pricing ($0.50 vs $0.20/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini 3 Flash and Grok 4 Fast?

Gemini 3 Flash is developed by Google and Grok 4 Fast is developed by xAI.

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