Model Comparison

Grok 4.5 vs Phi 4 ReasoningWhich is better in 2026?

Grok 4.5 significantly outperforms across most benchmarks.

Verdict: Grok 4.5 vs Phi 4 Reasoning — which is better?

Grok 4.5 (by xAI) and Phi 4 Reasoning (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.

Grok 4.5 outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning is better at 0 benchmarks. Grok 4.5 significantly outperforms across most benchmarks.

Choose Grok 4.5 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 if…

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

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Grok 4.5 outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning is better at 0 benchmarks.

Grok 4.5 significantly outperforms across most benchmarks.

Tue Jul 21 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Grok 4.5 specifies input context (500,000 tokens).

xAI
Grok 4.5
Input500,000 tokens
Output- tokens
Microsoft
Phi 4 Reasoning
Input- tokens
Output- tokens
Tue Jul 21 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Grok 4.5 supports multimodal inputs, whereas Phi 4 Reasoning does not.

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

Grok 4.5

Text
Images
Audio
Video

Phi 4 Reasoning

Text
Images
Audio
Video

License

Usage and distribution terms

Grok 4.5 is licensed under a proprietary license, while Phi 4 Reasoning uses MIT.

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

Grok 4.5

Proprietary

Closed source

Phi 4 Reasoning

MIT

Open weights

Release Timeline

When each model was launched

Grok 4.5 was released on 2026-07-16, while Phi 4 Reasoning was released on 2025-04-30.

Grok 4.5 is 15 months newer than Phi 4 Reasoning.

Grok 4.5

Jul 16, 2026

5 days ago

1.2yr newer
Phi 4 Reasoning

Apr 30, 2025

1.2 years ago

Knowledge Cutoff

When training data ends

Grok 4.5 has a knowledge cutoff of 2026-02-01, while Phi 4 Reasoning has a cutoff of 2025-03-01.

Grok 4.5 has more recent training data (up to 2026-02-01), making it potentially better informed about events through that date compared to Phi 4 Reasoning (2025-03-01).

Grok 4.5

Feb 2026

11 mo newer
Phi 4 Reasoning

Mar 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

xAI
Larger context window (500,000 tokens)
Supports multimodal inputs
Higher GPQA score (93.0% vs 65.8%)
Microsoft
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

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

Grok 4.5
✓ Preferred
Phi 4 Reasoning
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok 4.5
Microsoft
Phi 4 Reasoning

FAQ

Common questions about Grok 4.5 vs Phi 4 Reasoning.

Which is better, Grok 4.5 or Phi 4 Reasoning?

Grok 4.5 significantly outperforms across most benchmarks. Grok 4.5 is made by xAI and Phi 4 Reasoning is made by Microsoft. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Grok 4.5 compare to Phi 4 Reasoning in benchmarks?

Grok 4.5 scores GPQA: 93.0%, Terminal-Bench 2.1: 83.3%, Artificial Analysis Coding Agent Index v1.1: 76.0%, SWE-Bench Pro: 64.7%, AA-Omniscience Index: 63.0%. Phi 4 Reasoning scores FlenQA: 97.7%, HumanEval+: 92.9%, IFEval: 83.4%, OmniMath: 76.6%, AIME 2024: 75.3%.

What are the context window sizes for Grok 4.5 and Phi 4 Reasoning?

Grok 4.5 supports 500K tokens and Phi 4 Reasoning 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 Grok 4.5 and Phi 4 Reasoning?

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

Who makes Grok 4.5 and Phi 4 Reasoning?

Grok 4.5 is developed by xAI and Phi 4 Reasoning is developed by Microsoft.

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