Model Comparison

Gemini 3.5 Flash-Lite vs Grok 4 FastWhich is better in 2026?

Comparing Gemini 3.5 Flash-Lite and Grok 4 Fast across benchmarks, pricing, and capabilities.

Verdict: Gemini 3.5 Flash-Lite vs Grok 4 Fast — which is better?

Gemini 3.5 Flash-Lite (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.

On price, Grok 4 Fast is roughly 3.1x 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 3.5 Flash-Lite if…

  • you want the most recent training data — it shipped Jul 2026

Choose Grok 4 Fast if…

  • cost matters — it's about 3.1x cheaper per token
  • you process long inputs — it offers a 2,000,000 token context window

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Gemini 3.5 Flash-Lite and Grok 4 Fastdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Grok 4 Fast costs less

For input processing, Gemini 3.5 Flash-Lite ($0.30/1M tokens) is 1.5x more expensive than Grok 4 Fast ($0.20/1M tokens).

For output processing, Gemini 3.5 Flash-Lite ($2.50/1M tokens) is 5.0x more expensive than Grok 4 Fast ($0.50/1M tokens).

In conclusion, Gemini 3.5 Flash-Lite is more expensive than Grok 4 Fast.*

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

Lowest available price from all providers
Tue Jul 21 2026 • llm-stats.com
Google
Gemini 3.5 Flash-Lite
Input tokens$0.30
Output tokens$2.50
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 3.5 Flash-Lite's 1,048,576 tokens. Gemini 3.5 Flash-Lite can generate longer responses up to 65,536 tokens, while Grok 4 Fast is limited to 30,000 tokens.

Google
Gemini 3.5 Flash-Lite
Input1,048,576 tokens
Output65,536 tokens
xAI
Grok 4 Fast
Input2,000,000 tokens
Output30,000 tokens
Tue Jul 21 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Gemini 3.5 Flash-Lite and Grok 4 Fast support multimodal inputs.

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

Gemini 3.5 Flash-Lite

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 3.5 Flash-Lite

Proprietary

Closed source

Grok 4 Fast

Proprietary

Closed source

Release Timeline

When each model was launched

Gemini 3.5 Flash-Lite was released on 2026-07-21, while Grok 4 Fast was released on 2025-08-28.

Gemini 3.5 Flash-Lite is 11 months newer than Grok 4 Fast.

Gemini 3.5 Flash-Lite

Jul 21, 2026

0 days ago

10mo newer
Grok 4 Fast

Aug 28, 2025

10 months ago

Knowledge Cutoff

When training data ends

Gemini 3.5 Flash-Lite has a documented knowledge cutoff of 2026-03-31, while Grok 4 Fast's cutoff date is not specified.

We can confirm Gemini 3.5 Flash-Lite's training data extends to 2026-03-31, but cannot make a direct comparison without Grok 4 Fast's cutoff date.

Gemini 3.5 Flash-Lite

Mar 2026

Grok 4 Fast

—

Provider Availability

Gemini 3.5 Flash-Lite is available from Google. Grok 4 Fast is available from xAI.

Gemini 3.5 Flash-Lite

google logo
Google
Input Price:Input: $0.30/1MOutput Price:Output: $2.50/1M

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

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Google

No standout differentiators in the data we have for this pair.

xAI
Larger context window (2,000,000 tokens)
Less expensive input tokens
Less expensive output tokens

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Gemini 3.5 Flash-Lite and Grok 4 Fast side-by-side, then vote on the output you prefer.

Gemini 3.5 Flash-Lite
✓ Preferred
Grok 4 Fast
Open in Playground
AI Model Comparison Table
Feature
Google
Gemini 3.5 Flash-Lite
xAI
Grok 4 Fast

FAQ

Common questions about Gemini 3.5 Flash-Lite vs Grok 4 Fast.

Which is better, Gemini 3.5 Flash-Lite or Grok 4 Fast?

Gemini 3.5 Flash-Lite (Google) and Grok 4 Fast (xAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Gemini 3.5 Flash-Lite compare to Grok 4 Fast in benchmarks?

Gemini 3.5 Flash-Lite scores CharXiv-R: 76.5%, OSWorld-Verified: 74.0%, SWE-Bench Pro: 54.2%, Terminal-Bench 2.1: 54.0%, MLE-Bench: 39.2%. Grok 4 Fast scores SimpleQA: 95.0%, HMMT 2025: 93.3%, AIME 2025: 92.0%, GPQA: 85.7%, LiveCodeBench: 80.0%.

Is Gemini 3.5 Flash-Lite cheaper than Grok 4 Fast?

Grok 4 Fast is 1.5x cheaper for input tokens. Gemini 3.5 Flash-Lite costs $0.30/M input and $2.50/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 3.5 Flash-Lite and Grok 4 Fast?

Gemini 3.5 Flash-Lite 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 3.5 Flash-Lite and Grok 4 Fast?

Key differences include context window (1.0M vs 2.0M), input pricing ($0.30 vs $0.20/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Gemini 3.5 Flash-Lite and Grok 4 Fast?

Gemini 3.5 Flash-Lite is developed by Google and Grok 4 Fast is developed by xAI.

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