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Claude Fable 5.1 vs Grok-2

Claude Fable 5.1 leads the LLM Stats Score 57.0 to 11.6. Grok-2 is 5.0x cheaper per token.

Anthropic · xAI · Updated for 2026

Which is better?

Claude Fable 5.1 leads the overall LLM Stats Score 57.0 to 11.6, ranking #1 overall.

On price, Grok-2 is roughly 5.0x 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 57.0 and ranks #1 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • 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-2

  • cost matters — it's about 5.0x cheaper per token

At a glance

The differences that matter most.

Claude Fable 5.1
Anthropic
Grok-2
xAI
Core performance indexes
LLM Stats Score
57.0
#1
11.6
#246
Reasoning
54.5
#4
11.6
#242
Coding
37.0
#17
9.3
#167
Cost, coverage & limits
Benchmark wins
—
—
Input price
$10.00 / M
$2.00 / M
Output price
$50.00 / M
$10.00 / M
Context window
1,000,000
128,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

1 shared
Index
Claude Fable 5.1
Grok-2
Vision
40.8#1
8.0#133
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

7 reported for Claude Fable 5.1 · 8 for Grok-2

No common benchmarks found

Claude Fable 5.1 and Grok-2don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Grok-2 costs less

For input processing, Claude Fable 5.1 ($10.00/1M tokens) is 5.0x more expensive than Grok-2 ($2.00/1M tokens).

For output processing, Claude Fable 5.1 ($50.00/1M tokens) is 5.0x more expensive than Grok-2 ($10.00/1M tokens).

In conclusion, Claude Fable 5.1 is more expensive than Grok-2.*

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

Lowest available price from all providers
Thu Sep 03 2026 • llm-stats.com
Anthropic
Claude Fable 5.1
Input tokens$10.00
Output tokens$50.00
Best providerAnthropic
xAI
Grok-2
Input tokens$2.00
Output tokens$10.00
Best providerxAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Claude Fable 5.1 accepts 1,000,000 input tokens compared to Grok-2's 128,000 tokens. Claude Fable 5.1 can generate longer responses up to 128,000 tokens, while Grok-2 is limited to 8,000 tokens.

Anthropic
Claude Fable 5.1
Input1,000,000 tokens
Output128,000 tokens
xAI
Grok-2
Input128,000 tokens
Output8,000 tokens
Thu Sep 03 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Fable 5.1 and Grok-2 support multimodal inputs.

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

Claude Fable 5.1

Text
Images
Audio
Video

Grok-2

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.

Claude Fable 5.1

Proprietary

Closed source

Grok-2

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Fable 5.1 was released on 2026-09-01, while Grok-2 was released on 2024-08-13.

Claude Fable 5.1 is 25 months newer than Grok-2.

Claude Fable 5.1

Sep 1, 2026

1 days ago

2.1yr newer
Grok-2

Aug 13, 2024

2.1 years ago

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

Claude Fable 5.1 is available from Anthropic. Grok-2 is available from xAI.

Claude Fable 5.1

anthropic logo
Anthropic
Input Price:Input: $10.00/1MOutput Price:Output: $50.00/1M

Grok-2

xai logo
xAI
Input Price:Input: $2.00/1MOutput Price:Output: $10.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Fable 5.1 and Grok-2 side-by-side, then vote on the output you prefer.

Claude Fable 5.1
✓ Preferred
Grok-2
Open in Playground

FAQ

Common questions about Claude Fable 5.1 vs Grok-2.

Which is better, Claude Fable 5.1 or Grok-2?

Claude Fable 5.1 leads the LLM Stats Score 57.0 to 11.6. Claude Fable 5.1 is made by Anthropic and Grok-2 is made by xAI. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Claude Fable 5.1 compare to Grok-2 in benchmarks?

Claude Fable 5.1 scores OSWorld 2.0: 77.9%, CursorBench v3.2: 73.4%, Humanity's Last Exam: 65.0%, GDPval-AA: 61.8%, Terminal-Bench 4.0: 55.8%. Grok-2 scores DocVQA: 93.6%, HumanEval: 88.4%, MMLU: 87.5%, MATH: 76.1%, MMLU-Pro: 75.5%.

Is Claude Fable 5.1 cheaper than Grok-2?

Grok-2 is 5.0x cheaper for input tokens. Claude Fable 5.1 costs $10.00/M input and $50.00/M output via anthropic. Grok-2 costs $2.00/M input and $10.00/M output via xai.

What are the context window sizes for Claude Fable 5.1 and Grok-2?

Claude Fable 5.1 supports 1.0M tokens and Grok-2 supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Fable 5.1 and Grok-2?

Key differences include LLM Stats Score (57.0 vs 11.6), context window (1.0M vs 128K), input pricing ($10.00 vs $2.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Fable 5.1 and Grok-2?

Claude Fable 5.1 is developed by Anthropic and Grok-2 is developed by xAI.

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