GPT-5.4 vs Phi-4 Reasoning Vision 15B
GPT-5.4 (2026) and Phi-4 Reasoning Vision 15B (2026) are frontier reasoning models from OpenAI and Microsoft Research. GPT-5.4 ships a 1.05m-token context window, while Phi-4 Reasoning Vision 15B ships a not-yet-sourced context window. On Massive Multi-discipline Multimodal Understanding, GPT-5.4 leads by 27.8 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Phi-4 Reasoning Vision 15B is safer overall; choose GPT-5.4 when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | GPT-5.4 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | multimodal apps |
| Decision fit | Coding, RAG, and Agents | Vision |
| Context window | 1.05m | — |
| Cheapest output | $15/1M tokens | - |
| Provider routes | 4 tracked | 0 tracked |
| Shared benchmarks | Massive Multi-discipline Multimodal Understanding leader | 1 shared |
Decision tradeoffs
- GPT-5.4 holds a shared-benchmark lead on Massive Multi-discipline Multimodal Understanding, ahead by 27.8 points.
- GPT-5.4 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.4 has broader tracked provider coverage for fallback and route flexibility.
- GPT-5.4 uniquely exposes Reasoning, JSON / Tool use, and Structured outputs in local model data.
- Local decision data tags GPT-5.4 for Coding, RAG, and Agents.
- Local decision data tags Phi-4 Reasoning Vision 15B for Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5.4
$5,750
Cheapest tracked route/tier: OpenAI API
Phi-4 Reasoning Vision 15B
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 GPT-5.4 and Phi-4 Reasoning Vision 15B; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning, JSON / Tool use, and Structured outputs before moving production traffic.
- No overlapping tracked provider route is sourced for Phi-4 Reasoning Vision 15B and GPT-5.4; plan for SDK, billing, or endpoint changes.
- GPT-5.4 adds Reasoning, JSON / Tool use, and Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-03-05 | 2026-03-12 |
| Context window | 1.05m | — |
| Parameters | — | 15B |
| Architecture | Decoder Only | - |
| License | Proprietary | MITOSI-approved |
| Openness | Proprietary | Open source |
| Weights | Not released | Unknown |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | 2025-08 | 2025-03 |
Pricing and availability
| Pricing attribute | GPT-5.4 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Input price |
| - |
| Output price |
| - |
| Providers | - |
Capabilities
| Capability | GPT-5.4 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| JSON / Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | GPT-5.4 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Massive Multi-discipline Multimodal Understanding | 82.1 | 54.3 |
Continue comparing
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.