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Phi-3.5 Medium vs Phi-4

A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.

Updated

Phi-3.5 Medium specs · Phi-4 specs
Verdict by category
  • PriceTie

    Neither model publishes per-token API pricing.

  • Context windowPhi-3.5 Medium

    Phi-3.5 Medium accepts 128K tokens vs 16K, 8.0× the room for long documents and codebases.

  • BenchmarksPhi-4

    Phi-4 leads in 1 of 1 shared benchmarks; the biggest gap is on MMLU (broad academic knowledge), where it scores 84.8 vs 78.9.

  • ModalitiesTie

    Both handle text.

  • OpennessTie

    Both ship open weights, self-host either one.

It's a genuine coin-flip between Phi-3.5 Medium and Phi-4: 1 category wins each, with the rest tied. Neither model publishes per-token API pricing. Phi-3.5 Medium accepts 128K tokens vs 16K, 8.0× the room for long documents and codebases.

Phi-4 leads in 1 of 1 shared benchmarks; the biggest gap is on MMLU (broad academic knowledge), where it scores 84.8 vs 78.9. Both target the same set of modalities (text), so the deciding factors are price, context, and raw quality. Both ship open weights, self-host either one.

Phi-4 is the newer of the two, released 4 months after Phi-3.5 Medium, which usually means a more recent knowledge cutoff and updated safety post-training. Phi-3.5 Medium is usually picked for on device and edge deployment workloads, while Phi-4 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

SpecPhi-3.5 MediumPhi-4
ProviderMicrosoftMicrosoft
ReleasedAug 2024Dec 2024
Modalitiestexttext
Context window128K tokens16K tokens
Max output,,
Input · 1MPricing not publishedPricing not published
Output · 1MPricing not publishedPricing not published
Knowledge cutoff,,
Open weightsYes (MIT)Yes (MIT)
API availableYesYes

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, vs ,
  • Heavy usage, 1M in / 500k out per day, vs ,
  • RAG workload, 5M in / 200k out per day, 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).

Price calculator

Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.

  • Phi-3.5 MediumPricing unavailable
  • Phi-4Pricing unavailable

Benchmarks compared

Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.

Phi-3.5 MediumPhi-4
  • MMLU78.984.8
  • HumanEval,82.6
Pick Phi-3.5 Medium if

Phi-3.5 Medium fits when…

  • MIT license
  • 128k context
  • Strong reasoning at 14B
  • Long-context tasks, handles 128K tokens vs 16K for Phi-4.
Pick Phi-4 if

Phi-4 fits when…

  • Exceptional quality at 14B parameters
  • MIT license, clean commercial use
  • Strong on math
Don't want either?

Consider Mistral Large 2

Mistral's flagship API model, strong on code and reasoning, EU-friendly hosting.

See Mistral Large 2 specsPhi-3.5 Medium vs Mistral Large 2Phi-4 vs Mistral Large 2

Frequently asked

  • Is Phi-3.5 Medium or Phi-4 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?
    Phi-3.5 Medium accepts 128K tokens vs 16K for Phi-4.
  • Is Phi-3.5 Medium or Phi-4 better for coding?
    Both Phi-3.5 Medium and Phi-4 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?
    Both ship with open weights. Phi-3.5 Medium is licensed under MIT; Phi-4 under MIT.
  • When were Phi-3.5 Medium and Phi-4 released?
    Phi-3.5 Medium was released by Microsoft on 2024-08-20. Phi-4 was released by Microsoft on 2024-12-12.
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