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Claude Opus 4.1 vs Phi 4 Reasoning Plus

Claude Opus 4.1 has a slight edge in benchmark performance.

Anthropic · Microsoft · Updated for 2026

Which is better?

Claude Opus 4.1 outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning Plus is better at 0 benchmarks. Claude Opus 4.1 has a slight edge in benchmark performance.

Based on current benchmark, pricing, and model metadata for 2026.

Choose Claude Opus 4.1

  • you want the most recent training data — it shipped Aug 2025

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 Opus 4.1
Anthropic
Phi 4 Reasoning Plus
Microsoft
Benchmark wins
1 of 2
1 of 2
Input price
$15.00 / M
— / M
Output price
$75.00 / M
— / M
Context window
200,000
—
Released
Aug 2025
Apr 2025
License
Proprietary
MIT

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Opus 4.1 outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning Plus is better at 0 benchmarks.

Claude Opus 4.1 has a slight edge in benchmark performance.

Mon Aug 24 2026 • llm-stats.com

Arena Performance

Playground indexes and blind preference scores

Context Window

Maximum input and output token capacity

Only Claude Opus 4.1 specifies input context (200,000 tokens). Only Claude Opus 4.1 specifies output context (32,000 tokens).

Anthropic
Claude Opus 4.1
Input200,000 tokens
Output32,000 tokens
Microsoft
Phi 4 Reasoning Plus
Input- tokens
Output- tokens
Mon Aug 24 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 4.1 supports multimodal inputs, whereas Phi 4 Reasoning Plus does not.

Claude Opus 4.1 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Opus 4.1

Text
Images
Audio
Video

Phi 4 Reasoning Plus

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Opus 4.1 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 Opus 4.1

Proprietary

Closed source

Phi 4 Reasoning Plus

MIT

Open weights

Release Timeline

When each model was launched

Claude Opus 4.1 was released on 2025-08-05, while Phi 4 Reasoning Plus was released on 2025-04-30.

Claude Opus 4.1 is 3 months newer than Phi 4 Reasoning Plus.

Claude Opus 4.1

Aug 5, 2025

1.1 years ago

3mo 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 Opus 4.1'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 Opus 4.1's cutoff date.

Claude Opus 4.1

—

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 Opus 4.1 and Phi 4 Reasoning Plus side-by-side, then vote on the output you prefer.

Claude Opus 4.1
✓ Preferred
Phi 4 Reasoning Plus
Open in Playground

FAQ

Common questions about Claude Opus 4.1 vs Phi 4 Reasoning Plus.

Which is better, Claude Opus 4.1 or Phi 4 Reasoning Plus?

Claude Opus 4.1 has a slight edge in benchmark performance. Claude Opus 4.1 is made by Anthropic and Phi 4 Reasoning Plus is made by Microsoft. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Opus 4.1 compare to Phi 4 Reasoning Plus in benchmarks?

Claude Opus 4.1 scores MMMLU: 89.5%, TAU-bench Retail: 82.4%, GPQA: 80.9%, AIME 2025: 78.0%, MMMU (validation): 77.1%. 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 Opus 4.1 and Phi 4 Reasoning Plus?

Claude Opus 4.1 supports 200K 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 Opus 4.1 and Phi 4 Reasoning Plus?

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

Who makes Claude Opus 4.1 and Phi 4 Reasoning Plus?

Claude Opus 4.1 is developed by Anthropic and Phi 4 Reasoning Plus is developed by Microsoft.

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