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Claude Fable 5.1 vs Grok Code Fast 1

Claude Fable 5.1 leads the LLM Stats Score 55.7 to 20.7. Grok Code Fast 1 is 38.1x cheaper per token.

Anthropic · xAI · Updated for 2026

Which is better?

Claude Fable 5.1 leads the overall LLM Stats Score 55.7 to 20.7, ranking #2 overall.

On price, Grok Code Fast 1 is roughly 38.1x 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 55.7 and ranks #2 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 Code Fast 1

  • cost matters — it's about 38.1x cheaper per token

At a glance

The differences that matter most.

Claude Fable 5.1
Anthropic
Grok Code Fast 1
xAI
Core performance indexes
LLM Stats Score
55.7
#2
20.7
#192
Reasoning
52.8
#5
20.6
#185
Coding
35.5
#27
12.9
#140
Cost, coverage & limits
Benchmark wins
—
—
Input price
$10.00 / M
$0.20 / M
Output price
$50.00 / M
$1.50 / M
Context window
1,000,000
256,000

Individual benchmarks

7 reported for Claude Fable 5.1 · 1 for Grok Code Fast 1

No common benchmarks found

Claude Fable 5.1 and Grok Code Fast 1don'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 Code Fast 1 costs less

For input processing, Claude Fable 5.1 ($10.00/1M tokens) is 50.0x more expensive than Grok Code Fast 1 ($0.20/1M tokens).

For output processing, Claude Fable 5.1 ($50.00/1M tokens) is 33.3x more expensive than Grok Code Fast 1 ($1.50/1M tokens).

In conclusion, Claude Fable 5.1 is more expensive than Grok Code Fast 1.*

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

Lowest available price from all providers
Mon Sep 21 2026 • llm-stats.com
Anthropic
Claude Fable 5.1
Input tokens$10.00
Output tokens$50.00
Best providerAnthropic
xAI
Grok Code Fast 1
Input tokens$0.20
Output tokens$1.50
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 Code Fast 1's 256,000 tokens. Claude Fable 5.1 can generate longer responses up to 128,000 tokens, while Grok Code Fast 1 is limited to 10,000 tokens.

Anthropic
Claude Fable 5.1
Input1,000,000 tokens
Output128,000 tokens
xAI
Grok Code Fast 1
Input256,000 tokens
Output10,000 tokens
Mon Sep 21 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Fable 5.1 supports multimodal inputs, whereas Grok Code Fast 1 does not.

Claude Fable 5.1 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Fable 5.1

Text
Images
Audio
Video

Grok Code Fast 1

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 Code Fast 1

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Fable 5.1 was released on 2026-09-01, while Grok Code Fast 1 was released on 2025-08-28.

Claude Fable 5.1 is 12 months newer than Grok Code Fast 1.

Claude Fable 5.1

Sep 1, 2026

2 weeks ago

1.0yr newer
Grok Code Fast 1

Aug 28, 2025

1.1 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 Code Fast 1 is available from xAI.

Claude Fable 5.1

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

Grok Code Fast 1

xai logo
xAI
Input Price:Input: $0.20/1MOutput Price:Output: $1.50/1M
* 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 Code Fast 1 side-by-side, then vote on the output you prefer.

Claude Fable 5.1
✓ Preferred
Grok Code Fast 1
Open in Playground

FAQ

Common questions about Claude Fable 5.1 vs Grok Code Fast 1.

Which is better, Claude Fable 5.1 or Grok Code Fast 1?

Claude Fable 5.1 leads the LLM Stats Score 55.7 to 20.7. Claude Fable 5.1 is made by Anthropic and Grok Code Fast 1 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 Code Fast 1 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 Code Fast 1 scores SWE-Bench Verified: 70.8%.

Is Claude Fable 5.1 cheaper than Grok Code Fast 1?

Grok Code Fast 1 is 50.0x cheaper for input tokens. Claude Fable 5.1 costs $10.00/M input and $50.00/M output via anthropic. Grok Code Fast 1 costs $0.20/M input and $1.50/M output via xai.

What are the context window sizes for Claude Fable 5.1 and Grok Code Fast 1?

Claude Fable 5.1 supports 1.0M tokens and Grok Code Fast 1 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 Claude Fable 5.1 and Grok Code Fast 1?

Key differences include LLM Stats Score (55.7 vs 20.7), context window (1.0M vs 256K), input pricing ($10.00 vs $0.20/M), multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Fable 5.1 and Grok Code Fast 1?

Claude Fable 5.1 is developed by Anthropic and Grok Code Fast 1 is developed by xAI.

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