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Model Comparison

o1 vs Phi 4 Reasoning PlusWhich is better in 2026?

Both models are evenly matched across the benchmarks.

Verdict: o1 vs Phi 4 Reasoning Plus — which is better?

o1 (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.

o1 outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning Plus is better at 1 benchmark (AIME 2024). Both models are evenly matched across the benchmarks.

Choose o1 if…

  • you want predictable pricing at $15.00/M input and $60.00/M output

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

2 benchmarks

o1 outperforms in 1 benchmarks (GPQA), while Phi 4 Reasoning Plus is better at 1 benchmark (AIME 2024).

Both models are evenly matched across the benchmarks.

Fri Aug 07 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only o1 specifies input context (200,000 tokens). Only o1 specifies output context (100,000 tokens).

OpenAI
o1
Input200,000 tokens
Output100,000 tokens
Microsoft
Phi 4 Reasoning Plus
Input- tokens
Output- tokens
Fri Aug 07 2026 • llm-stats.com

License

Usage and distribution terms

o1 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.

o1

Proprietary

Closed source

Phi 4 Reasoning Plus

MIT

Open weights

Release Timeline

When each model was launched

o1 was released on 2024-12-17, while Phi 4 Reasoning Plus was released on 2025-04-30.

Phi 4 Reasoning Plus is 4 months newer than o1.

o1

Dec 17, 2024

1.6 years ago

Phi 4 Reasoning Plus

Apr 30, 2025

1.3 years ago

4mo newer

Knowledge Cutoff

When training data ends

Phi 4 Reasoning Plus has a documented knowledge cutoff of 2025-03-01, while o1'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 o1's cutoff date.

o1

—

Phi 4 Reasoning Plus

Mar 2025

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (200,000 tokens)
Higher GPQA score (78.0% vs 68.9%)
Microsoft
Has open weights
Higher AIME 2024 score (81.3% vs 74.3%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against o1 and Phi 4 Reasoning Plus side-by-side, then vote on the output you prefer.

o1
✓ Preferred
Phi 4 Reasoning Plus
Open in Playground
AI Model Comparison Table
Feature
OpenAI
o1
Microsoft
Phi 4 Reasoning Plus

FAQ

Common questions about o1 vs Phi 4 Reasoning Plus.

Which is better, o1 or Phi 4 Reasoning Plus?

Both models are evenly matched across the benchmarks. o1 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 o1 compare to Phi 4 Reasoning Plus in benchmarks?

o1 scores GSM8k: 97.1%, MATH: 96.4%, GPQA Physics: 92.8%, MMLU: 91.8%, MGSM: 89.3%. 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 o1 and Phi 4 Reasoning Plus?

o1 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 o1 and Phi 4 Reasoning Plus?

Key differences include licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes o1 and Phi 4 Reasoning Plus?

o1 is developed by OpenAI and Phi 4 Reasoning Plus is developed by Microsoft.

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