Phi-2 vs Phi-4 Mini
Phi-2 (2023) and Phi-4 Mini (2024) are general-purpose language models from Microsoft Research. Phi-2 ships a not-yet-sourced context window, while Phi-4 Mini ships a not-yet-sourced context window. On Google-Proof Q&A, Phi-2 leads by 16.0 pts. On pricing, Phi-2 costs $0.05/1M input tokens versus $0.05/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
Pick Phi-2 for reasoning; Phi-4 Mini is better when provider fit matters more.
Decision scorecard
Local evidence first| Signal | Phi-2 | Phi-4 Mini |
|---|---|---|
| Decision fit | Coding, Classification, and JSON / Tool use | Classification |
| Context window | — | — |
| Cheapest output | $0.25/1M tokens | $0.15/1M tokens |
| Provider routes | 5 tracked | 3 tracked |
| Shared benchmarks | Google-Proof Q&A leader | 2 rows |
Decision tradeoffs
- Phi-2 leads the largest shared benchmark signal on Google-Proof Q&A by 16.0 points.
- Phi-2 has broader tracked provider coverage for fallback and procurement flexibility.
- Phi-2 uniquely exposes Structured outputs in local model data.
- Local decision data tags Phi-2 for Coding, Classification, and JSON / Tool use.
- Phi-4 Mini has the lower cheapest tracked output price at $0.15/1M tokens.
- Local decision data tags Phi-4 Mini for Classification.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
Phi-2
$103
Cheapest tracked route: Replicate API
Phi-4 Mini
$77.50
Cheapest tracked route: Novita AI
Estimated monthly gap: $25.00. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Fireworks AI; start route-level A/B tests there.
- Phi-4 Mini is $0.1/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Structured outputs before moving production traffic.
- Provider overlap exists on Fireworks AI; start route-level A/B tests there.
- Phi-2 is $0.1/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Phi-2 adds Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2023-12-12 | 2024-12-13 |
| Context window | — | — |
| Parameters | 2.7B | 3.8B |
| Architecture | decoder only | - |
| License | Open Source | Microsoft Research |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Phi-2 | Phi-4 Mini |
|---|---|---|
| Input price | $0.05/1M tokens | $0.05/1M tokens |
| Output price | $0.25/1M tokens | $0.15/1M tokens |
| Providers |
Capabilities
| Capability | Phi-2 | Phi-4 Mini |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
Benchmarks
| Benchmark | Phi-2 | Phi-4 Mini |
|---|---|---|
| Google-Proof Q&A | 41.2 | 25.2 |
| Massive Multitask Language Understanding | 68.3 | 67.3 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has Phi-2 at 41.2 and Phi-4 Mini at 25.2, with Phi-2 ahead by 16.0 points; Massive Multitask Language Understanding has Phi-2 at 68.3 and Phi-4 Mini at 67.3, with Phi-2 ahead by 1 points. The largest visible gap is 16.0 points on Google-Proof Q&A, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on structured outputs: Phi-2. 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.
For cost, Phi-2 lists $0.05/1M input and $0.25/1M output tokens, while Phi-4 Mini lists $0.05/1M input and $0.15/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Phi-4 Mini lower by about $0.03 per million blended tokens. Availability is 5 providers versus 3, so concentration risk also matters.
Choose Phi-2 when provider fit and broader provider choice are central to the workload. Choose Phi-4 Mini when provider fit are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which is cheaper, Phi-2 or Phi-4 Mini?
Phi-2 is cheaper on tracked token pricing. Phi-2 costs $0.05/1M input and $0.25/1M output tokens. Phi-4 Mini costs $0.05/1M input and $0.15/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Phi-2 or Phi-4 Mini open source?
Phi-2 is listed under Open Source. Phi-4 Mini is listed under Microsoft Research. 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 structured outputs, Phi-2 or Phi-4 Mini?
Phi-2 has the clearer documented structured outputs signal in this comparison. If structured outputs is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Phi-2 and Phi-4 Mini?
Phi-2 is available on Microsoft Foundry, Cloudflare Workers AI, Together AI, Fireworks AI, and Replicate API. Phi-4 Mini is available on Fireworks AI, NVIDIA NIM, and Novita AI. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Phi-2 over Phi-4 Mini?
Pick Phi-2 for reasoning; Phi-4 Mini is better when provider fit matters more. If your workload also depends on provider fit, start with Phi-2; if it depends on provider fit, run the same evaluation with Phi-4 Mini.
Continue comparing
Last reviewed: 2026-05-16. Data sourced from public model cards and provider documentation.