Phi 3.5 Vision Instruct vs Phi-4 Mini Flash Reasoning
Phi 3.5 Vision Instruct (2024) and Phi-4 Mini Flash Reasoning (2025) are frontier reasoning models from Microsoft Research. Phi 3.5 Vision Instruct ships a 128k-token context window, while Phi-4 Mini Flash Reasoning ships a 128k-token context window. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads. It focuses on practical selection signals rather than broad model-family marketing.
Phi-4 Mini Flash Reasoning is safer overall; choose Phi 3.5 Vision Instruct when vision-heavy evaluation matters.
Decision scorecard
Local evidence first| Signal | Phi 3.5 Vision Instruct | Phi-4 Mini Flash Reasoning |
|---|---|---|
| Best for | multimodal apps | reasoning-heavy apps |
| Decision fit | Long context and Vision | Long context |
| Context window | 128k | 128k |
| Cheapest output | - | - |
| Provider routes | 0 tracked | 1 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Phi 3.5 Vision Instruct uniquely exposes Vision and Multimodal in local model data.
- Local decision data tags Phi 3.5 Vision Instruct for Long context and Vision.
- Phi-4 Mini Flash Reasoning has broader tracked provider coverage for fallback and route flexibility.
- Phi-4 Mini Flash Reasoning uniquely exposes Reasoning in local model data.
- Local decision data tags Phi-4 Mini Flash Reasoning for Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Phi 3.5 Vision Instruct
Unavailable
No complete token price in local provider data
Phi-4 Mini Flash 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 3.5 Vision Instruct and Phi-4 Mini Flash Reasoning; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision and Multimodal before moving production traffic.
- Phi-4 Mini Flash Reasoning adds Reasoning in local capability data.
- No overlapping tracked provider route is sourced for Phi-4 Mini Flash Reasoning and Phi 3.5 Vision Instruct; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning before moving production traffic.
- Phi 3.5 Vision Instruct adds Vision and Multimodal in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-08-20 | 2025-12-01 |
| Context window | 128k | 128k |
| Parameters | 4.1B | 3.8B |
| Architecture | Decoder Only | Decoder Only |
| License | MITOSI-approved | MITOSI-approved |
| Openness | Open source | Open source |
| Weights | Unknown | Unknown |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: permitted | Commercial use: permitted |
| Knowledge cutoff | 2023-10 | 2025-02 |
Pricing and availability
| Pricing attribute | Phi 3.5 Vision Instruct | Phi-4 Mini Flash Reasoning |
|---|---|---|
| Input price | - | - |
| Output price | - | - |
| Providers | - |
Pricing not yet sourced for either model.
Capabilities
| Capability | Phi 3.5 Vision Instruct | Phi-4 Mini Flash Reasoning |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | No | Yes |
| JSON / Tool use | No | No |
| Structured outputs | No | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
Continue comparing
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Popular comparisons for Phi 3.5 Vision Instruct
Popular comparisons for Phi-4 Mini Flash Reasoning
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Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.