Mistral Medium 3.5 vs Microsoft Phi-4

Mistral AI · France  |  Microsoft · US · Updated June 2026

Quick verdict

Pick Mistral Medium 3.5 for strong intelligence-for-size — artificial analysis intelligence index 30, near the top of its price tier or 128b dense open-weight model — self-hostable. Pick Microsoft Phi-4 for strong reasoning for a small 14b open-weight model or mit-licensed — fully self-hostable at no per-token cost. On a tight budget at scale, Microsoft Phi-4 is the value pick.

Mistral Medium 3.5 (Mistral AI, France) and Microsoft Phi-4 (Microsoft, US) line up two different AI ecosystems against each other — a comparison that is as much about cost philosophy and openness as raw capability. Mistral Medium 3.5 is mistral's efficient 128B open-weight model — a single dense model unifying reasoning and coding that punches above its size on independent tests (AA Index 30). Microsoft Phi-4 is microsoft's MIT-licensed 14B open model — strong reasoning for its size and very cheap, but a tiny 16K context and text-only. They diverge most on price and context window — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecMistral Medium 3.5Microsoft Phi-4
ProviderMistral AI (France) Microsoft (US)
ReleasedApril 29, 2026 January 10, 2025
Context window256K (~384 pages) 16K (~25 pages)
Price (in/out)$1.5/$7.5 per 1M tokens $0.07/$0.14 per 1M tokens
Open weight?Yes — self-hostable Yes — self-hostable
Modalitiestext, image, code text, code
SWE-Bench VerifiedNot published Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Strong intelligence-for-size — Artificial Analysis Intelligence Index 30, near the top of its price tier

Mistral Medium 3.5

Microsoft Phi-4 is comparatively weak here — no first-party per-token API; hosted prices are third-party

128B dense open-weight model — self-hostable

Mistral Medium 3.5

Microsoft Phi-4 is comparatively weak here — an early-2025 small model, outclassed on hard tasks by 2026 flagships

Unifies reasoning and coding into one model with an adjustable reasoning effort

Mistral Medium 3.5

Mistral's efficient 128B open-weight model — a single dense model unifying reasoning and coding that punches above its size on independent tests (AA Index 30) — and it carries the larger 256K context.

Strong reasoning for a small 14B open-weight model

Microsoft Phi-4

Microsoft's MIT-licensed 14B open model — strong reasoning for its size and very cheap, but a tiny 16K context and text-only — and it runs cheaper at $0.07/$0.14 per 1M tokens.

MIT-licensed — fully self-hostable at no per-token cost

Microsoft Phi-4

At $0.07/$0.14 per 1M tokens it undercuts Mistral Medium 3.5 ($1.5/$7.5 per 1M tokens), and that gap compounds at volume.

Runs on modest or local hardware

Microsoft Phi-4

Microsoft Phi-4 lists runs on modest or local hardware among its strengths; Mistral Medium 3.5 does not.

Lowest cost at scale

Microsoft Phi-4

At $0.07/$0.14 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Largest single-prompt input

Mistral Medium 3.5

Its 256K window is about 16× larger than Microsoft Phi-4's 16K, fitting roughly 384 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

Microsoft Phi-4

At $0.07/$0.14 per 1M tokens it undercuts Mistral Medium 3.5, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

Mistral Medium 3.5

Larger 256K window fits more in one prompt.

Anyone whose priority is strong intelligence-for-size — artificial analysis intelligence index 30, near the top of its price tier

Mistral Medium 3.5

It is specifically built for that.

Anyone whose priority is strong reasoning for a small 14b open-weight model

Microsoft Phi-4

That is its strongest area.

An enterprise with regional data-residency rules

Microsoft Phi-4 or Mistral Medium 3.5

Origin (France vs US) affects where data is processed and which compliance regime applies — check the provider's terms for your region.

Mistral Medium 3.5: where it fits

Mistral's efficient 128B open-weight model — a single dense model unifying reasoning and coding that punches above its size on independent tests (AA Index 30). Released April 29, 2026 by Mistral AI, it is built for strong intelligence-for-size — Artificial Analysis Intelligence Index 30, near the top of its price tier, 128B dense open-weight model — self-hostable, unifies reasoning and coding into one model with an adjustable reasoning effort, and 256K context with text and image input.

Its trade-offs are real: below the absolute frontier — a value/efficiency pick, not a flagship-beater, output pricing ($7.50/M) is higher than the cheapest Chinese rivals, license framing ('open' vs enterprise) varies across sources — confirm terms for commercial use, and no native video or audio. At $1.5 in / $7.5 out per million tokens, it sits in the mid price band.

Microsoft Phi-4: where it fits

Microsoft's MIT-licensed 14B open model — strong reasoning for its size and very cheap, but a tiny 16K context and text-only. Released January 10, 2025 by Microsoft, it is built for strong reasoning for a small 14B open-weight model, mIT-licensed — fully self-hostable at no per-token cost, runs on modest or local hardware, and very cheap hosted inference at about $0.07/$0.14.

Its trade-offs: a tiny 16K context — by far the smallest window in this comparison, text only — no image, audio or video input, an early-2025 small model, outclassed on hard tasks by 2026 flagships, and no first-party per-token API; hosted prices are third-party. At $0.07 in / $0.14 out per million tokens, it sits in the budget price band.

The bottom line for this matchup

This is less "which is smarter" and more "which ecosystem fits." Mistral Medium 3.5 (France) and Microsoft Phi-4 (US) differ on pricing philosophy, data-residency, and tooling as much as on raw scores. Microsoft Phi-4 is the cheaper option, which matters at volume. The pragmatic move is to run one real task through both and judge the outputs against your own constraints — including where your data is allowed to be processed.

Want both Mistral Medium 3.5 and Microsoft Phi-4 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.

See pricing

Frequently asked questions

Is Mistral Medium 3.5 or Microsoft Phi-4 better for coding?

Public SWE-Bench figures are not available for either model, so the honest test is your own repository — run an identical real bug through both. By design, Mistral Medium 3.5 leans toward strong intelligence-for-size — artificial analysis intelligence index 30, near the top of its price tier while Microsoft Phi-4 leans toward strong reasoning for a small 14b open-weight model, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, Mistral Medium 3.5 or Microsoft Phi-4?

Microsoft Phi-4 is cheaper — $1.5/$7.5 per 1M tokens vs $0.07/$0.14 per 1M tokens, roughly 21× apart on input.

Which has the bigger context window?

Mistral Medium 3.5 — 256K vs 16K, about 16× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both Mistral Medium 3.5 and Microsoft Phi-4 together?

Yes — a multi-model platform like LumiChats gives you Mistral Medium 3.5, Microsoft Phi-4 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.

Which is newer, Mistral Medium 3.5 or Microsoft Phi-4?

Mistral Medium 3.5 — released April 29, 2026, about 16 months after Microsoft Phi-4.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.