Claude 3.5 Sonnet vs Phi 4 Reasoning Plus
Both models are evenly matched across the benchmarks.
Anthropic · Microsoft · Updated for 2026
Which is better?
Claude 3.5 Sonnet outperforms in 1 benchmarks (MMLU-Pro), while Phi 4 Reasoning Plus is better at 1 benchmark (GPQA). Both models are evenly matched across the benchmarks.
Based on current benchmark, pricing, and model metadata for 2026.
Choose Claude 3.5 Sonnet
- you want predictable pricing at $3.00/M input and $15.00/M output
Choose Phi 4 Reasoning Plus
- you want the most recent training data — it shipped Apr 2025
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
Claude 3.5 Sonnet outperforms in 1 benchmarks (MMLU-Pro), while Phi 4 Reasoning Plus is better at 1 benchmark (GPQA).
Both models are evenly matched across the benchmarks.
Arena Performance
Playground indexes and blind preference scores
Context Window
Maximum input and output token capacity
Only Claude 3.5 Sonnet specifies input context (200,000 tokens). Only Claude 3.5 Sonnet specifies output context (200,000 tokens).
Input Capabilities
Supported data types and modalities
Claude 3.5 Sonnet supports multimodal inputs, whereas Phi 4 Reasoning Plus does not.
Claude 3.5 Sonnet can handle both text and other forms of data like images, making it suitable for multimodal applications.
Claude 3.5 Sonnet
Phi 4 Reasoning Plus
License
Usage and distribution terms
Claude 3.5 Sonnet 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.
Proprietary
Closed source
MIT
Open weights
Release Timeline
When each model was launched
Claude 3.5 Sonnet was released on 2024-06-21, while Phi 4 Reasoning Plus was released on 2025-04-30.
Phi 4 Reasoning Plus is 10 months newer than Claude 3.5 Sonnet.
Jun 21, 2024
2.2 years ago
Apr 30, 2025
1.3 years ago
10mo newerKnowledge Cutoff
When training data ends
Phi 4 Reasoning Plus has a documented knowledge cutoff of 2025-03-01, while Claude 3.5 Sonnet'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 3.5 Sonnet's cutoff date.
—
Mar 2025
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude 3.5 Sonnet and Phi 4 Reasoning Plus side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude 3.5 Sonnet vs Phi 4 Reasoning Plus.