Model Comparison

GPT-4.5 vs Phi 4 Reasoning PlusWhich is better in 2026?

GPT-4.5 shows notably better performance in the majority of benchmarks.

Verdict: GPT-4.5 vs Phi 4 Reasoning Plus — which is better?

GPT-4.5 (by OpenAI) 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.

GPT-4.5 outperforms in 2 benchmarks (GPQA, IFEval), while Phi 4 Reasoning Plus is better at 1 benchmark (AIME 2024). GPT-4.5 shows notably better performance in the majority of benchmarks.

Choose GPT-4.5 if…

  • you want the strongest raw capability — it leads on 2 of 3 shared benchmarks

Choose Phi 4 Reasoning Plus if…

  • you want the most recent training data — it shipped Apr 2025
  • you need open weights you can self-host or fine-tune

Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

GPT-4.5 outperforms in 2 benchmarks (GPQA, IFEval), while Phi 4 Reasoning Plus is better at 1 benchmark (AIME 2024).

GPT-4.5 shows notably better performance in the majority of benchmarks.

Wed Jul 29 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only GPT-4.5 specifies input context (128,000 tokens). Only GPT-4.5 specifies output context (4,096 tokens).

OpenAI
GPT-4.5
Input128,000 tokens
Output4,096 tokens
Microsoft
Phi 4 Reasoning Plus
Input- tokens
Output- tokens
Wed Jul 29 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-4.5 supports multimodal inputs, whereas Phi 4 Reasoning Plus does not.

GPT-4.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-4.5

Text
Images
Audio
Video

Phi 4 Reasoning Plus

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-4.5 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.

GPT-4.5

Proprietary

Closed source

Phi 4 Reasoning Plus

MIT

Open weights

Release Timeline

When each model was launched

GPT-4.5 was released on 2025-02-27, while Phi 4 Reasoning Plus was released on 2025-04-30.

Phi 4 Reasoning Plus is 2 months newer than GPT-4.5.

GPT-4.5

Feb 27, 2025

1.4 years ago

Phi 4 Reasoning Plus

Apr 30, 2025

1.2 years ago

2mo newer

Knowledge Cutoff

When training data ends

Phi 4 Reasoning Plus has a documented knowledge cutoff of 2025-03-01, while GPT-4.5'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 GPT-4.5's cutoff date.

GPT-4.5

—

Phi 4 Reasoning Plus

Mar 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (128,000 tokens)
Supports multimodal inputs
Higher GPQA score (69.5% vs 68.9%)
Higher IFEval score (88.2% vs 84.9%)
Microsoft
Has open weights
Higher AIME 2024 score (81.3% vs 36.7%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-4.5 and Phi 4 Reasoning Plus side-by-side, then vote on the output you prefer.

GPT-4.5
✓ Preferred
Phi 4 Reasoning Plus
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-4.5
Microsoft
Phi 4 Reasoning Plus

FAQ

Common questions about GPT-4.5 vs Phi 4 Reasoning Plus.

Which is better, GPT-4.5 or Phi 4 Reasoning Plus?

GPT-4.5 shows notably better performance in the majority of benchmarks. GPT-4.5 is made by OpenAI 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 GPT-4.5 compare to Phi 4 Reasoning Plus in benchmarks?

GPT-4.5 scores GSM8k: 97.0%, MMLU: 90.8%, CharXiv-D: 90.0%, IFEval: 88.2%, HumanEval: 88.0%. 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 GPT-4.5 and Phi 4 Reasoning Plus?

GPT-4.5 supports 128K 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 GPT-4.5 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 GPT-4.5 and Phi 4 Reasoning Plus?

GPT-4.5 is developed by OpenAI and Phi 4 Reasoning Plus is developed by Microsoft.

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