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Claude Fable 5.1 vs Phi 4 Reasoning Plus

Claude Fable 5.1 leads the LLM Stats Score 57.0 to 15.3.

Anthropic · Microsoft · Updated for 2026

Which is better?

Claude Fable 5.1 leads the overall LLM Stats Score 57.0 to 15.3, ranking #1 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 57.0 and ranks #1 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you want the most recent training data — it shipped Sep 2026

Choose Phi 4 Reasoning Plus

  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Claude Fable 5.1
Anthropic
Phi 4 Reasoning Plus
Microsoft
Core performance indexes
LLM Stats Score
57.0
#1
15.3
#218
Reasoning
54.5
#4
15.6
#212
Coding
37.0
#17
5.8
#187
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 · 11 for Phi 4 Reasoning Plus

No common benchmarks found

Claude Fable 5.1 and Phi 4 Reasoning Plusdon'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
Microsoft
Phi 4 Reasoning Plus
Input- tokens
Output- tokens
Thu Sep 03 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Claude Fable 5.1 supports multimodal inputs, whereas Phi 4 Reasoning Plus 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

Phi 4 Reasoning Plus

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Fable 5.1 is licensed under a proprietary license, while Phi 4 Reasoning Plus uses MIT.

License differences may affect how you can use these models in commercial or open-source projects.

Claude Fable 5.1

Proprietary

Closed source

Phi 4 Reasoning Plus

MIT

Open weights

Release Timeline

When each model was launched

Claude Fable 5.1 was released on 2026-09-01, while Phi 4 Reasoning Plus was released on 2025-04-30.

Claude Fable 5.1 is 16 months newer than Phi 4 Reasoning Plus.

Claude Fable 5.1

Sep 1, 2026

1 days ago

1.3yr newer
Phi 4 Reasoning Plus

Apr 30, 2025

1.3 years ago

Knowledge Cutoff

When training data ends

Phi 4 Reasoning Plus has a documented knowledge cutoff of 2025-03-01, while Claude Fable 5.1's cutoff date is not specified.

We can confirm Phi 4 Reasoning Plus's training data extends to 2025-03-01, but cannot make a direct comparison without Claude Fable 5.1's cutoff date.

Claude Fable 5.1

—

Phi 4 Reasoning Plus

Mar 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Claude Fable 5.1 and Phi 4 Reasoning Plus side-by-side, then vote on the output you prefer.

Claude Fable 5.1
✓ Preferred
Phi 4 Reasoning Plus
Open in Playground

FAQ

Common questions about Claude Fable 5.1 vs Phi 4 Reasoning Plus.

Which is better, Claude Fable 5.1 or Phi 4 Reasoning Plus?

Claude Fable 5.1 leads the LLM Stats Score 57.0 to 15.3. Claude Fable 5.1 is made by Anthropic and Phi 4 Reasoning Plus is made by Microsoft. 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 Phi 4 Reasoning Plus 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%. Phi 4 Reasoning Plus scores FlenQA: 97.9%, HumanEval+: 92.3%, IFEval: 84.9%, OmniMath: 81.9%, AIME 2024: 81.3%.

What are the context window sizes for Claude Fable 5.1 and Phi 4 Reasoning Plus?

Claude Fable 5.1 supports 1.0M tokens and Phi 4 Reasoning Plus 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 Phi 4 Reasoning Plus?

Key differences include LLM Stats Score (57.0 vs 15.3), multimodal support (yes vs no), licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Fable 5.1 and Phi 4 Reasoning Plus?

Claude Fable 5.1 is developed by Anthropic and Phi 4 Reasoning Plus is developed by Microsoft.

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