GPT-4o vs Phi-4 Reasoning Vision 15B
GPT-4o (2024) and Phi-4 Reasoning Vision 15B (2026) are compact production models from OpenAI and Microsoft Research. GPT-4o ships a 128k-token context window, while Phi-4 Reasoning Vision 15B ships a not-yet-sourced context window. On Massive Multi-discipline Multimodal Understanding, GPT-4o leads by 14.8 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-4o when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | GPT-4o | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Best for | multimodal apps, tool-calling agents, and provider-routed production | multimodal apps |
| Decision fit | Coding, RAG, and Agents | Vision |
| Context window | 128k | — |
| Cheapest output | $10/1M tokens | - |
| Provider routes | 5 tracked | 0 tracked |
| Shared benchmarks | Massive Multi-discipline Multimodal Understanding leader | 1 shared |
Decision tradeoffs
- GPT-4o holds a shared-benchmark lead on Massive Multi-discipline Multimodal Understanding, ahead by 14.8 points.
- GPT-4o has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-4o has broader tracked provider coverage for fallback and procurement flexibility.
- GPT-4o uniquely exposes Function calling, Tool use, and Structured outputs in local model data.
- Local decision data tags GPT-4o 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-4o
$4,500
Cheapest tracked route/tier: Replicate 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-4o and Phi-4 Reasoning Vision 15B; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Function calling, Tool use, and Structured outputs before moving production traffic.
- No overlapping tracked provider route is sourced for Phi-4 Reasoning Vision 15B and GPT-4o; plan for SDK, billing, or endpoint changes.
- GPT-4o adds Function calling, Tool use, and Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-05-13 | 2026-03-12 |
| Context window | 128k | — |
| Parameters | — | 15B |
| Architecture | Decoder Only | - |
| License | Proprietary | MITOSI-approved |
| Openness | Proprietary | Open source |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | 2023-10 | 2025-03 |
Pricing and availability
| Pricing attribute | GPT-4o | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Input price | $2.50/1M tokens | - |
| Output price | $10/1M tokens | - |
| Providers | - |
Capabilities
| Capability | GPT-4o | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | No |
| Function calling | Yes | No |
| 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-4o | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Massive Multi-discipline Multimodal Understanding | 69.1 | 54.3 |
Deep dive
On shared benchmark coverage, Massive Multi-discipline Multimodal Understanding has GPT-4o at 69.1 and Phi-4 Reasoning Vision 15B at 54.3, with GPT-4o ahead by 14.8 points. The largest visible gap is 14.8 points on Massive Multi-discipline Multimodal Understanding, 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 function calling: GPT-4o, tool use: GPT-4o, structured outputs: GPT-4o, and code execution: GPT-4o. Both models share vision and multimodal input, 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: GPT-4o has $2.50/1M input tokens and Phi-4 Reasoning Vision 15B has no token price sourced yet. Provider availability is 5 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose GPT-4o when coding workflow support and broader provider choice are central to the workload. Choose Phi-4 Reasoning Vision 15B when vision-heavy evaluation are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Is GPT-4o or Phi-4 Reasoning Vision 15B open source?
GPT-4o is listed under Proprietary. Phi-4 Reasoning Vision 15B is listed under MIT. 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 vision, GPT-4o or Phi-4 Reasoning Vision 15B?
Both GPT-4o and Phi-4 Reasoning Vision 15B expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, GPT-4o or Phi-4 Reasoning Vision 15B?
Both GPT-4o and Phi-4 Reasoning Vision 15B expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for function calling, GPT-4o or Phi-4 Reasoning Vision 15B?
GPT-4o has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for tool use, GPT-4o or Phi-4 Reasoning Vision 15B?
GPT-4o has the clearer documented tool use signal in this comparison. If tool use is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GPT-4o and Phi-4 Reasoning Vision 15B?
GPT-4o is available on Replicate API, OpenRouter, Azure OpenAI, OpenAI API, and Vercel AI Gateway. Phi-4 Reasoning Vision 15B is available on the tracked providers still being sourced. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-15. Data sourced from public model cards and provider documentation.