Model Comparison

Grok 4 Fast vs Grok-4.1 Thinking

Comparing Grok 4 Fast and Grok-4.1 Thinking across benchmarks, pricing, and capabilities.

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Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Grok 4 Fast and Grok-4.1 Thinking don'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, Grok 4 Fast ($0.20/1M tokens) is 15.0x cheaper than Grok-4.1 Thinking ($3.00/1M tokens).

For output processing, Grok 4 Fast ($0.50/1M tokens) is 30.0x cheaper than Grok-4.1 Thinking ($15.00/1M tokens).

In conclusion, Grok-4.1 Thinking is more expensive than Grok 4 Fast.*

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

Lowest available price from all providers
Fri May 22 2026 • llm-stats.com
xAI
Grok 4 Fast
Input tokens$0.20
Output tokens$0.50
Best providerxAI
xAI
Grok-4.1 Thinking
Input tokens$3.00
Output tokens$15.00
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 Grok-4.1 Thinking's 256,000 tokens. Grok 4 Fast can generate longer responses up to 30,000 tokens, while Grok-4.1 Thinking is limited to 8,000 tokens.

xAI
Grok 4 Fast
Input2,000,000 tokens
Output30,000 tokens
xAI
Grok-4.1 Thinking
Input256,000 tokens
Output8,000 tokens
Fri May 22 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Grok 4 Fast and Grok-4.1 Thinking support multimodal inputs.

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

Grok 4 Fast

Text
Images
Audio
Video

Grok-4.1 Thinking

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.

Grok 4 Fast

Proprietary

Closed source

Grok-4.1 Thinking

Proprietary

Closed source

Release Timeline

When each model was launched

Grok 4 Fast was released on 2025-08-28, while Grok-4.1 Thinking was released on 2025-11-17.

Grok-4.1 Thinking is 3 months newer than Grok 4 Fast.

Grok 4 Fast

Aug 28, 2025

8 months ago

Grok-4.1 Thinking

Nov 17, 2025

6 months ago

2mo newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

Grok 4 Fast is available from xAI. Grok-4.1 Thinking is available from xAI.

Grok 4 Fast

xai logo
xAI
Input Price:Input: $0.20/1MOutput Price:Output: $0.50/1M

Grok-4.1 Thinking

xai logo
xAI
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

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

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

Detailed Comparison

AI Model Comparison Table
Feature
xAI
Grok 4 Fast
xAI
Grok-4.1 Thinking

FAQ

Common questions about Grok 4 Fast vs Grok-4.1 Thinking.

Which is better, Grok 4 Fast or Grok-4.1 Thinking?

Grok 4 Fast (xAI) and Grok-4.1 Thinking (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 Grok 4 Fast compare to Grok-4.1 Thinking in benchmarks?

Grok 4 Fast scores SimpleQA: 95.0%, HMMT 2025: 93.3%, AIME 2025: 92.0%, GPQA: 85.7%, LiveCodeBench: 80.0%. Grok-4.1 Thinking scores Creative Writing v3: 86.1%, WMDP: 84.0%, EQ-Bench: 79.3%, ProtocolQA: 79.0%, LMArena Text Leaderboard: 74.2%.

Is Grok 4 Fast cheaper than Grok-4.1 Thinking?

Grok 4 Fast is 15.0x cheaper for input tokens. Grok 4 Fast costs $0.20/M input and $0.50/M output via xai. Grok-4.1 Thinking costs $3.00/M input and $15.00/M output via xai.

What are the context window sizes for Grok 4 Fast and Grok-4.1 Thinking?

Grok 4 Fast supports 2.0M tokens and Grok-4.1 Thinking supports 256K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Grok 4 Fast and Grok-4.1 Thinking?

Key differences include context window (2.0M vs 256K), input pricing ($0.20 vs $3.00/M). See the full comparison above for benchmark-by-benchmark results.