Phi-3 MediumvsClaude Opus 4
Microsoft vs Anthropic — Side-by-side model comparison
Head-to-Head Comparison
| Metric | Phi-3 Medium | Claude Opus 4 |
|---|---|---|
| Provider | Microsoft | |
| Arena Rank | — | #1 |
| Context Window | 128K | 200K |
| Input Pricing | Free (open)/1M tokens | $5.00/1M tokens |
| Output Pricing | Free (open)/1M tokens | $25.00/1M tokens |
| Parameters | 14B | Undisclosed |
| Open Source | Yes | No |
| Best For | Balanced performance, reasoning, coding | Complex reasoning, coding, agentic tasks |
| Release Date | May 21, 2024 | May 22, 2025 |
Phi-3 Medium
Phi-3 Medium, developed by Microsoft, is a mid-size open-source model with 14 billion parameters and a 128K token context window. The model occupies the middle ground in Microsoft's Phi-3 family, offering stronger reasoning and coding capabilities than Phi-3 Mini while remaining deployable on standard enterprise GPU hardware. It benefits from the same high-quality synthetic and curated training data approach that distinguishes the Phi model line. Phi-3 Medium handles coding, analysis, summarization, and structured reasoning tasks competently. Free and open-source, it supports commercial deployment and fine-tuning without licensing costs. The model targets enterprise applications where Phi-3 Mini's capabilities are insufficient but full-scale frontier models are either too expensive or impractical to deploy. It runs on a single GPU, making it accessible for organizations with moderate compute budgets.
Claude Opus 4
Claude Opus 4 is Anthropic's most powerful AI model, holding the #1 position on the Chatbot Arena leaderboard. It represents a breakthrough in extended thinking and agentic capabilities, able to work autonomously on complex multi-step tasks for hours. With a 200K token context window, it excels at analyzing entire codebases, lengthy legal documents, and research papers in a single pass. The model demonstrates exceptional performance in coding (setting new benchmarks on SWE-bench), advanced reasoning, and nuanced writing tasks. Its agentic capabilities allow it to use tools, navigate computers, and execute multi-step workflows with minimal human oversight. Opus 4 is the preferred choice for enterprises requiring the highest quality output on mission-critical tasks where accuracy and depth matter more than speed or cost.
View Anthropic profile →Key Differences: Phi-3 Medium vs Claude Opus 4
Claude Opus 4 supports a larger context window (200K), allowing it to process longer documents in a single request.
Phi-3 Medium is open-source (free to self-host and fine-tune) while Claude Opus 4 is proprietary (API-only access).
When to use Phi-3 Medium
- +You need to self-host or fine-tune the model
- +Your use case involves balanced performance, reasoning, coding
When to use Claude Opus 4
- +You need to process long documents (200K context)
- +You prefer a managed API without infrastructure overhead
- +Your use case involves complex reasoning, coding, agentic tasks
The Verdict
Claude Opus 4 wins our head-to-head comparison with 4 out of 5 category wins. It's the stronger choice for complex reasoning, coding, agentic tasks, though Phi-3 Medium holds an edge in balanced performance, reasoning, coding.
Last compared: April 2026 · Data sourced from public benchmarks and official pricing pages