Mistral Magistral Small 2509 vs Phi-3 Medium 128K
Mistral Magistral Small 2509 (2025) and Phi-3 Medium 128K (2024) are compact production models from MistralAI and Microsoft Research. Mistral Magistral Small 2509 ships a not-yet-sourced context window, while Phi-3 Medium 128K ships a 128K-token context window. On pricing, Mistral Magistral Small 2509 costs $0.5/1M input tokens versus $0.5/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Mistral Magistral Small 2509 is safer overall; choose Phi-3 Medium 128K when provider fit matters.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-01 | 2024-05-21 |
| Context window | — | 128K |
| Parameters | — | 14B |
| Architecture | - | decoder only |
| License | Proprietary | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Mistral Magistral Small 2509 | Phi-3 Medium 128K |
|---|---|---|
| Input price | $0.5/1M tokens | $0.5/1M tokens |
| Output price | $1.5/1M tokens | $1.5/1M tokens |
| Providers |
Capabilities
| Capability | Mistral Magistral Small 2509 | Phi-3 Medium 128K |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | No |
| 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 is close: both models cover the core production surface. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, Mistral Magistral Small 2509 lists $0.5/1M input and $1.5/1M output tokens, while Phi-3 Medium 128K lists $0.5/1M input and $1.5/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Mistral Magistral Small 2509 lower by about $0 per million blended tokens. Availability is 1 providers versus 2, so concentration risk also matters.
Choose Mistral Magistral Small 2509 when provider fit are central to the workload. Choose Phi-3 Medium 128K when provider fit and broader provider choice 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.
FAQ
Which is cheaper, Mistral Magistral Small 2509 or Phi-3 Medium 128K?
Mistral Magistral Small 2509 is cheaper on tracked token pricing. Mistral Magistral Small 2509 costs $0.5/1M input and $1.5/1M output tokens. Phi-3 Medium 128K costs $0.5/1M input and $1.5/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Mistral Magistral Small 2509 or Phi-3 Medium 128K open source?
Mistral Magistral Small 2509 is listed under Proprietary. Phi-3 Medium 128K is listed under Open Source. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Where can I run Mistral Magistral Small 2509 and Phi-3 Medium 128K?
Mistral Magistral Small 2509 is available on AWS Bedrock. Phi-3 Medium 128K is available on Microsoft Foundry and NVIDIA NIM. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Mistral Magistral Small 2509 over Phi-3 Medium 128K?
Mistral Magistral Small 2509 is safer overall; choose Phi-3 Medium 128K when provider fit matters. If your workload also depends on provider fit, start with Mistral Magistral Small 2509; if it depends on provider fit, run the same evaluation with Phi-3 Medium 128K.
Continue comparing
Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.