Model Comparison

Claude Opus 5 vs Phi 4 Reasoning PlusWhich is better in 2026?

Comparing Claude Opus 5 and Phi 4 Reasoning Plus across benchmarks, pricing, and capabilities.

Verdict: Claude Opus 5 vs Phi 4 Reasoning Plus — which is better?

Claude Opus 5 (by Anthropic) and Phi 4 Reasoning Plus (by Microsoft) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Choose Claude Opus 5 if…

  • you want the most recent training data — it shipped Jul 2026

Choose Phi 4 Reasoning Plus if…

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

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Claude Opus 5 and Phi 4 Reasoning Plusdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Claude Opus 5 specifies input context (1,000,000 tokens). Only Claude Opus 5 specifies output context (128,000 tokens).

Anthropic
Claude Opus 5
Input1,000,000 tokens
Output128,000 tokens
Microsoft
Phi 4 Reasoning Plus
Input- tokens
Output- tokens
Sat Jul 25 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 5 supports multimodal inputs, whereas Phi 4 Reasoning Plus does not.

Claude Opus 5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Opus 5

Text
Images
Audio
Video

Phi 4 Reasoning Plus

Text
Images
Audio
Video

License

Usage and distribution terms

Claude Opus 5 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 5

Proprietary

Closed source

Phi 4 Reasoning Plus

MIT

Open weights

Release Timeline

When each model was launched

Claude Opus 5 was released on 2026-07-24, while Phi 4 Reasoning Plus was released on 2025-04-30.

Claude Opus 5 is 15 months newer than Phi 4 Reasoning Plus.

Claude Opus 5

Jul 24, 2026

1 days ago

1.2yr newer
Phi 4 Reasoning Plus

Apr 30, 2025

1.2 years ago

Knowledge Cutoff

When training data ends

Phi 4 Reasoning Plus has a documented knowledge cutoff of 2025-03-01, while Claude Opus 5'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 5's cutoff date.

Claude Opus 5

—

Phi 4 Reasoning Plus

Mar 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Larger context window (1,000,000 tokens)
Supports multimodal inputs
Microsoft
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Claude Opus 5 and Phi 4 Reasoning Plus side-by-side, then vote on the output you prefer.

Claude Opus 5
✓ Preferred
Phi 4 Reasoning Plus
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Opus 5
Microsoft
Phi 4 Reasoning Plus

FAQ

Common questions about Claude Opus 5 vs Phi 4 Reasoning Plus.

Which is better, Claude Opus 5 or Phi 4 Reasoning Plus?

Claude Opus 5 (Anthropic) and Phi 4 Reasoning Plus (Microsoft) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Claude Opus 5 compare to Phi 4 Reasoning Plus in benchmarks?

Claude Opus 5 scores BrowseComp: 90.8%, BioMysteryBench: 90.1%, OSWorld 2.0: 70.6%, DeepSWE 1.1: 68.8%, Humanity's Last Exam: 64.7%. 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 5 and Phi 4 Reasoning Plus?

Claude Opus 5 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 Opus 5 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 5 and Phi 4 Reasoning Plus?

Claude Opus 5 is developed by Anthropic and Phi 4 Reasoning Plus is developed by Microsoft.

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