Phi-3 Medium 128K vs Phi-4 Mini Reasoning
Phi-3 Medium 128K (2024) and Phi-4 Mini Reasoning (2026) are frontier reasoning models from Microsoft Research. Phi-3 Medium 128K ships a 128K-token context window, while Phi-4 Mini Reasoning ships a not-yet-sourced context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
Phi-4 Mini Reasoning is safer overall; choose Phi-3 Medium 128K when provider fit matters.
Decision scorecard
Local evidence first| Signal | Phi-3 Medium 128K | Phi-4 Mini Reasoning |
|---|---|---|
| Decision fit | Coding, Long context, and Classification | General |
| Context window | 128K | — |
| Cheapest output | $1.5/1M tokens | - |
| Provider routes | 2 tracked | 0 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Phi-3 Medium 128K has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Phi-3 Medium 128K has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Phi-3 Medium 128K for Coding, Long context, and Classification.
- Phi-4 Mini Reasoning uniquely exposes Reasoning in local model data.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
Phi-3 Medium 128K
$775
Cheapest tracked route: Microsoft Foundry
Phi-4 Mini Reasoning
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Phi-3 Medium 128K and Phi-4 Mini Reasoning; plan for SDK, billing, or endpoint changes.
- Phi-4 Mini Reasoning adds Reasoning in local capability data.
- No overlapping tracked provider route is sourced for Phi-4 Mini Reasoning and Phi-3 Medium 128K; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-05-21 | 2026-05-16 |
| Context window | 128K | — |
| Parameters | 14B | — |
| Architecture | decoder only | - |
| License | Open Source | Proprietary |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Phi-3 Medium 128K | Phi-4 Mini Reasoning |
|---|---|---|
| Input price | $0.5/1M tokens | - |
| Output price | $1.5/1M tokens | - |
| Providers | - |
Capabilities
| Capability | Phi-3 Medium 128K | Phi-4 Mini Reasoning |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | Yes |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | No |
| Code execution | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: Phi-4 Mini Reasoning. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: Phi-3 Medium 128K has $0.5/1M input tokens and Phi-4 Mini Reasoning has no token price sourced yet. Provider availability is 2 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Phi-3 Medium 128K when provider fit and broader provider choice are central to the workload. Choose Phi-4 Mini Reasoning when reasoning depth are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency. For teams standardizing a stack, that distinction is often the difference between a benchmark win and a reliable deployment.
FAQ
Is Phi-3 Medium 128K or Phi-4 Mini Reasoning open source?
Phi-3 Medium 128K is listed under Open Source. Phi-4 Mini Reasoning is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for reasoning mode, Phi-3 Medium 128K or Phi-4 Mini Reasoning?
Phi-4 Mini Reasoning has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Phi-3 Medium 128K and Phi-4 Mini Reasoning?
Phi-3 Medium 128K is available on Microsoft Foundry and NVIDIA NIM. Phi-4 Mini Reasoning is available on the tracked providers still being sourced. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Phi-3 Medium 128K over Phi-4 Mini Reasoning?
Phi-4 Mini Reasoning is safer overall; choose Phi-3 Medium 128K when provider fit matters. If your workload also depends on provider fit, start with Phi-3 Medium 128K; if it depends on reasoning depth, run the same evaluation with Phi-4 Mini Reasoning.
Continue comparing
Last reviewed: 2026-05-16. Data sourced from public model cards and provider documentation.