Claude Fable 5.1 vs Grok 4.5
Claude Fable 5.1 leads the LLM Stats Score 56.8 to 45.5. Grok 4.5 is 6.7x cheaper per token.
Anthropic · xAI · Updated for 2026
Which is better?
Claude Fable 5.1 leads the overall LLM Stats Score 56.8 to 45.5, ranking #2 overall.
In the 1 individual benchmarks reported for both models, Claude Fable 5.1 wins 1; this is a narrower head-to-head signal than the composite indexes.
On price, Grok 4.5 is roughly 6.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Claude Fable 5.1 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Claude Fable 5.1
- overall performance matters — it scores 56.8 and ranks #2 on LLM Stats
- your work emphasizes reasoning and agents — it leads those capability indexes
- you value its reported benchmark strengths — it wins 1 of 1 exact shared results
- you process long inputs — it offers a 1,000,000 token context window
- you want the most recent training data — it shipped Sep 2026
Choose Grok 4.5
- cost matters — it's about 6.7x cheaper per token
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
7 reported for Claude Fable 5.1 · 15 for Grok 4.5
Claude Fable 5.1 outperforms in 1 benchmarks (Terminal-Bench 4.0), while Grok 4.5 is better at 0 benchmarks.
Claude Fable 5.1 significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Fable 5.1 ($10.00/1M tokens) is 5.0x more expensive than Grok 4.5 ($2.00/1M tokens).
For output processing, Claude Fable 5.1 ($50.00/1M tokens) is 8.3x more expensive than Grok 4.5 ($6.00/1M tokens).
In conclusion, Claude Fable 5.1 is more expensive than Grok 4.5.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Claude Fable 5.1 accepts 1,000,000 input tokens compared to Grok 4.5's 500,000 tokens. Only Claude Fable 5.1 specifies output context (128,000 tokens).
Input capabilities
Documented input modalities across available providers
Both Claude Fable 5.1 and Grok 4.5 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Claude Fable 5.1
Grok 4.5
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 Fable 5.1 was released on 2026-09-01, while Grok 4.5 was released on 2026-07-16.
Claude Fable 5.1 is 2 months newer than Grok 4.5.
Sep 1, 2026
4 days ago
1mo newerJul 16, 2026
1 months ago
Knowledge Cutoff
When training data ends
Grok 4.5 has a documented knowledge cutoff of 2026-02-01, while Claude Fable 5.1's cutoff date is not specified.
We can confirm Grok 4.5's training data extends to 2026-02-01, but cannot make a direct comparison without Claude Fable 5.1's cutoff date.
—
Feb 2026
Provider Availability
Claude Fable 5.1 is available from Anthropic. Grok 4.5 is available from xAI.
Claude Fable 5.1
Grok 4.5
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Fable 5.1 and Grok 4.5 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Fable 5.1 vs Grok 4.5.