Model Comparison
Claude Haiku 4.5 vs Grok-4.1 Fast ReasoningWhich is better in 2026?
Comparing Claude Haiku 4.5 and Grok-4.1 Fast Reasoning across benchmarks, pricing, and capabilities.
Verdict: Claude Haiku 4.5 vs Grok-4.1 Fast Reasoning — which is better?
Claude Haiku 4.5 (by Anthropic) and Grok-4.1 Fast 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.
On price, Grok-4.1 Fast Reasoning is roughly 7.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Grok-4.1 Fast Reasoning also accepts a larger context window (2,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Claude Haiku 4.5 if…
- you want predictable pricing at $1.00/M input and $5.00/M output
Choose Grok-4.1 Fast Reasoning if…
- cost matters — it's about 7.3x cheaper per token
- you process long inputs — it offers a 2,000,000 token context window
- you want the most recent training data — it shipped Nov 2025
Performance Benchmarks
Comparative analysis across standard metrics
Claude Haiku 4.5 and Grok-4.1 Fast Reasoningdon'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, Claude Haiku 4.5 ($1.00/1M tokens) is 5.0x more expensive than Grok-4.1 Fast Reasoning ($0.20/1M tokens).
For output processing, Claude Haiku 4.5 ($5.00/1M tokens) is 10.0x more expensive than Grok-4.1 Fast Reasoning ($0.50/1M tokens).
In conclusion, Claude Haiku 4.5 is more expensive than Grok-4.1 Fast Reasoning.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Grok-4.1 Fast Reasoning accepts 2,000,000 input tokens compared to Claude Haiku 4.5's 200,000 tokens. Claude Haiku 4.5 can generate longer responses up to 64,000 tokens, while Grok-4.1 Fast Reasoning is limited to 30,000 tokens.
Input Capabilities
Supported data types and modalities
Both Claude Haiku 4.5 and Grok-4.1 Fast Reasoning support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Haiku 4.5
Grok-4.1 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
Claude Haiku 4.5 was released on 2025-10-15, while Grok-4.1 Fast Reasoning was released on 2025-11-17.
Grok-4.1 Fast Reasoning is 1 month newer than Claude Haiku 4.5.
Oct 15, 2025
9 months ago
Nov 17, 2025
8 months ago
1mo newerKnowledge Cutoff
When training data ends
Claude Haiku 4.5 has a documented knowledge cutoff of 2025-02-01, while Grok-4.1 Fast Reasoning's cutoff date is not specified.
We can confirm Claude Haiku 4.5's training data extends to 2025-02-01, but cannot make a direct comparison without Grok-4.1 Fast Reasoning's cutoff date.
Feb 2025
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Provider Availability
Claude Haiku 4.5 is available from Anthropic, Vertex AI. Grok-4.1 Fast Reasoning is available from xAI.
Claude Haiku 4.5
Grok-4.1 Fast Reasoning
Outputs Comparison
Key Takeaways
Claude Haiku 4.5
View detailsAnthropic
No standout differentiators in the data we have for this pair.
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Claude Haiku 4.5 and Grok-4.1 Fast Reasoning side-by-side, then vote on the output you prefer.
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FAQ
Common questions about Claude Haiku 4.5 vs Grok-4.1 Fast Reasoning.