GPT-4o mini vs Phi-3.5 Medium
A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.
Updated
GPT-4o mini specs · Phi-3.5 Medium specs- PriceGPT-4o mini
GPT-4o mini publishes pricing ($0.60 / 1M output tokens) while Phi-3.5 Medium does not.
- Context windowTie
Both ship a 128K-token context window.
- BenchmarksGPT-4o mini
GPT-4o mini leads in 1 of 1 shared benchmarks; the biggest gap is on MMLU (broad academic knowledge), where it scores 82.0 vs 78.9.
- ModalitiesGPT-4o mini
GPT-4o mini supports 2 modalities (text, vision) vs 1 for Phi-3.5 Medium.
- OpennessPhi-3.5 Medium
Phi-3.5 Medium ships open weights (MIT); GPT-4o mini is API-only.
On balance GPT-4o mini edges ahead, winning 3 of 5 categories against Phi-3.5 Medium's 1. GPT-4o mini publishes pricing ($0.60 / 1M output tokens) while Phi-3.5 Medium does not. Both ship a 128K-token context window.
GPT-4o mini leads in 1 of 1 shared benchmarks; the biggest gap is on MMLU (broad academic knowledge), where it scores 82.0 vs 78.9. They differ in modality coverage, GPT-4o mini handles text, vision while Phi-3.5 Medium handles text, which can be the deciding factor before you even look at benchmarks. Phi-3.5 Medium ships open weights (MIT); GPT-4o mini is API-only.
Phi-3.5 Medium is the newer of the two, released 1 months after GPT-4o mini, which usually means a more recent knowledge cutoff and updated safety post-training. GPT-4o mini is usually picked for customer support and summarization workloads, while Phi-3.5 Medium sees more deployments in on device and edge deployment. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.
Side-by-side specs
| Spec | GPT-4o mini | Phi-3.5 Medium |
|---|---|---|
| Provider | OpenAI | Microsoft |
| Released | Jul 2024 | Aug 2024 |
| Modalities | text, vision | text |
| Context window | 128K tokens | 128K tokens |
| Max output | , | , |
| Input · 1M | $0.15 / 1M tokens | Pricing not published |
| Output · 1M | $0.60 / 1M tokens | Pricing not published |
| Knowledge cutoff | , | , |
| Open weights | No | Yes (MIT) |
| API available | Yes | Yes |
Pricing at scale
What you'd actually pay at typical workloads. Numbers come from each model's published per-million-token rates.
- Light usage, 100k in / 50k out per day$1.35 vs ,
- Heavy usage, 1M in / 500k out per day$13.50 vs ,
- RAG workload, 5M in / 200k out per day$26.10 vs ,
Light usage, 100k in / 50k out per day: pricing not directly comparable (one or both models are missing public per-token rates). Heavy usage, 1M in / 500k out per day: pricing not directly comparable (one or both models are missing public per-token rates). RAG workload, 5M in / 200k out per day: pricing not directly comparable (one or both models are missing public per-token rates).
Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.
- GPT-4o mini$0.045
- Phi-3.5 MediumPricing unavailable
Benchmarks compared
Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.
- MMLU82.078.9
GPT-4o mini fits when…
- Cheap
- Fast
- Mature
- Multimodal needs covering vision.
Phi-3.5 Medium fits when…
- MIT license
- 128k context
- Strong reasoning at 14B
- Self-hosting and on-prem requirements, open weights (MIT).
Consider GPT-5.5
OpenAI's mid-cycle GPT-5 refresh, improved reasoning, tool use, and multimodal grounding over the 2025 launch.
Frequently asked
Is GPT-4o mini or Phi-3.5 Medium cheaper?
Per-token pricing isn't published for at least one of these models, check each model's spec page for current rates.Which has the larger context window?
Both GPT-4o mini and Phi-3.5 Medium ship a 128K-token context window.Is GPT-4o mini or Phi-3.5 Medium better for coding?
Both GPT-4o mini and Phi-3.5 Medium are competitive on coding benchmarks. See each model's individual spec page for HumanEval and SWE-bench scores where published. For an opinionated pick, consult our Best LLM for Coding ranking.Are either of these models open source?
Phi-3.5 Medium ships open weights (MIT). GPT-4o mini is API-only.When were GPT-4o mini and Phi-3.5 Medium released?
GPT-4o mini was released by OpenAI on 2024-07-18. Phi-3.5 Medium was released by Microsoft on 2024-08-20.
The week's AI launches, in your inbox.
One short email every Friday, new models, leaks, and quietly-shipped APIs you missed.