Model Comparison

GPT-5.6 Sol vs Phi 4 Reasoning PlusWhich is better in 2026?

GPT-5.6 Sol significantly outperforms across most benchmarks.

Verdict: GPT-5.6 Sol vs Phi 4 Reasoning Plus — which is better?

GPT-5.6 Sol (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-5.6 Sol outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning Plus is better at 0 benchmarks. GPT-5.6 Sol significantly outperforms across most benchmarks.

Choose GPT-5.6 Sol if…

  • you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • 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

1 benchmarks

GPT-5.6 Sol outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning Plus is better at 0 benchmarks.

GPT-5.6 Sol significantly outperforms across most benchmarks.

Sat Jul 18 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only GPT-5.6 Sol specifies input context (1,050,000 tokens). Only GPT-5.6 Sol specifies output context (128,000 tokens).

OpenAI
GPT-5.6 Sol
Input1,050,000 tokens
Output128,000 tokens
Microsoft
Phi 4 Reasoning Plus
Input- tokens
Output- tokens
Sat Jul 18 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

GPT-5.6 Sol supports multimodal inputs, whereas Phi 4 Reasoning Plus does not.

GPT-5.6 Sol can handle both text and other forms of data like images, making it suitable for multimodal applications.

GPT-5.6 Sol

Text
Images
Audio
Video

Phi 4 Reasoning Plus

Text
Images
Audio
Video

License

Usage and distribution terms

GPT-5.6 Sol 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-5.6 Sol

Proprietary

Closed source

Phi 4 Reasoning Plus

MIT

Open weights

Release Timeline

When each model was launched

GPT-5.6 Sol was released on 2026-07-09, while Phi 4 Reasoning Plus was released on 2025-04-30.

GPT-5.6 Sol is 15 months newer than Phi 4 Reasoning Plus.

GPT-5.6 Sol

Jul 9, 2026

1 weeks ago

1.2yr newer
Phi 4 Reasoning Plus

Apr 30, 2025

1.2 years ago

Knowledge Cutoff

When training data ends

GPT-5.6 Sol has a knowledge cutoff of 2026-02-16, while Phi 4 Reasoning Plus has a cutoff of 2025-03-01.

GPT-5.6 Sol has more recent training data (up to 2026-02-16), making it potentially better informed about events through that date compared to Phi 4 Reasoning Plus (2025-03-01).

GPT-5.6 Sol

Feb 2026

11 mo newer
Phi 4 Reasoning Plus

Mar 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (1,050,000 tokens)
Supports multimodal inputs
Higher GPQA score (94.6% vs 68.9%)
Microsoft
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-5.6 Sol and Phi 4 Reasoning Plus side-by-side, then vote on the output you prefer.

GPT-5.6 Sol
✓ Preferred
Phi 4 Reasoning Plus
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-5.6 Sol
Microsoft
Phi 4 Reasoning Plus

FAQ

Common questions about GPT-5.6 Sol vs Phi 4 Reasoning Plus.

Which is better, GPT-5.6 Sol or Phi 4 Reasoning Plus?

GPT-5.6 Sol significantly outperforms across most benchmarks. GPT-5.6 Sol 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-5.6 Sol compare to Phi 4 Reasoning Plus in benchmarks?

GPT-5.6 Sol scores Connectors: 100.0%, Capture-the-Flag Challenges (Internal): 96.7%, HealthBench Consensus: 95.5%, GPQA: 94.6%, MRCR v2 (8-needle): 91.5%. 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-5.6 Sol and Phi 4 Reasoning Plus?

GPT-5.6 Sol supports 1.1M 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-5.6 Sol 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-5.6 Sol and Phi 4 Reasoning Plus?

GPT-5.6 Sol is developed by OpenAI and Phi 4 Reasoning Plus is developed by Microsoft.

Related comparisons