Model Comparison
Grok 4 Fast vs Grok-4 Fast Reasoning
Comparing Grok 4 Fast and Grok-4 Fast Reasoning across benchmarks, pricing, and capabilities.
Performance Benchmarks
Comparative analysis across standard metrics
Grok 4 Fast and Grok-4 Fast Reasoning 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
For input processing, Grok 4 Fast ($0.20/1M tokens) costs the same as Grok-4 Fast Reasoning ($0.20/1M tokens).
For output processing, Grok 4 Fast ($0.50/1M tokens) costs the same as Grok-4 Fast Reasoning ($0.50/1M tokens).
In conclusion, Grok 4 Fast and Grok-4 Fast Reasoning cost the same.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Both models have the same input context window of 2,000,000 tokens. Both models can generate responses up to 30,000 tokens.
Input Capabilities
Supported data types and modalities
Both Grok 4 Fast and Grok-4 Fast Reasoning support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Grok 4 Fast
Grok-4 Fast 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
Both models were released on 2025-08-28.
They likely represent similar generations of model development.
Aug 28, 2025
8 months ago
Aug 28, 2025
8 months ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Grok 4 Fast is available from xAI. Grok-4 Fast Reasoning is available from xAI.
Grok 4 Fast
Grok-4 Fast Reasoning
Outputs Comparison
Key Takeaways
No standout differentiators in the data we have for this pair.
No standout differentiators in the data we have for this pair.
Detailed Comparison
| Feature | | |
|---|
FAQ
Common questions about Grok 4 Fast vs Grok-4 Fast Reasoning.