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Claude Fable 5.1 vs o1-pro

Claude Fable 5.1 leads the LLM Stats Score 54.8 to 20.0.

Anthropic · OpenAI · Updated for 2026

Which is better?

Claude Fable 5.1 leads the overall LLM Stats Score 54.8 to 20.0, ranking #5 overall.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Claude Fable 5.1

  • overall performance matters — it scores 54.8 and ranks #5 on LLM Stats
  • your work emphasizes reasoning — it leads those capability indexes
  • you want the most recent training data — it shipped Sep 2026

Choose o1-pro

  • you are already invested in the OpenAI ecosystem

At a glance

The differences that matter most.

Claude Fable 5.1
Anthropic
o1-pro
OpenAI
Core performance indexes
LLM Stats Score
54.8
#5
20.0
#185
Reasoning
52.1
#7
20.3
#175
Cost, coverage & limits
Benchmark wins
—
—
Input price
$10.00 / M
— / M
Output price
$50.00 / M
— / M
Context window
1,000,000
—

Individual benchmarks

7 reported for Claude Fable 5.1 · 2 for o1-pro

No common benchmarks found

Claude Fable 5.1 and o1-prodon'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

Context Window

Maximum input and output token capacity

Only Claude Fable 5.1 specifies input context (1,000,000 tokens). Only Claude Fable 5.1 specifies output context (128,000 tokens).

Anthropic
Claude Fable 5.1
Input1,000,000 tokens
Output128,000 tokens
OpenAI
o1-pro
Input- tokens
Output- tokens
Tue Sep 01 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Both Claude Fable 5.1 and o1-pro 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

o1-pro

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

o1-pro

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Fable 5.1 was released on 2026-09-01, while o1-pro was released on 2024-12-17.

Claude Fable 5.1 is 21 months newer than o1-pro.

Claude Fable 5.1

Sep 1, 2026

0 days ago

1.7yr newer
o1-pro

Dec 17, 2024

1.7 years ago

Knowledge Cutoff

When training data ends

o1-pro has a documented knowledge cutoff of 2023-09-30, while Claude Fable 5.1's cutoff date is not specified.

We can confirm o1-pro's training data extends to 2023-09-30, but cannot make a direct comparison without Claude Fable 5.1's cutoff date.

Claude Fable 5.1

—

o1-pro

Sep 2023

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Fable 5.1 and o1-pro side-by-side, then vote on the output you prefer.

Claude Fable 5.1
✓ Preferred
o1-pro
Open in Playground

FAQ

Common questions about Claude Fable 5.1 vs o1-pro.

Which is better, Claude Fable 5.1 or o1-pro?

Claude Fable 5.1 leads the LLM Stats Score 54.8 to 20.0. Claude Fable 5.1 is made by Anthropic and o1-pro is made by OpenAI. 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 o1-pro 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%. o1-pro scores AIME 2024: 86.0%, GPQA: 79.0%.

What are the context window sizes for Claude Fable 5.1 and o1-pro?

Claude Fable 5.1 supports 1.0M tokens and o1-pro supports an unknown number of 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 o1-pro?

Key differences include LLM Stats Score (54.8 vs 20.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Fable 5.1 and o1-pro?

Claude Fable 5.1 is developed by Anthropic and o1-pro is developed by OpenAI.

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