Claude Sonnet 4.6 vs Mistral Medium 3.5

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

Quick verdict

Pick Claude Sonnet 4.6 for best value in the claude family or everyday professional work. 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. Choose Mistral Medium 3.5 if you need self-hosting or data privacy; Claude Sonnet 4.6 if you want a managed API.

Claude Sonnet 4.6 (Anthropic, US) and Mistral Medium 3.5 (Mistral AI, France) line up two different AI ecosystems against each other — a comparison that is as much about cost philosophy and openness as raw capability. Claude Sonnet 4.6 is opus-class quality at lower cost; superseded as the default Sonnet by Claude Sonnet 5 (June 2026). 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). They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecClaude Sonnet 4.6Mistral Medium 3.5
ProviderAnthropic (US) Mistral AI (France)
ReleasedFebruary 17, 2026 April 29, 2026
Context window1M (~1,500 pages) 256K (~384 pages)
Price (in/out)$3/$15 per 1M tokens $1.5/$7.5 per 1M tokens
Open weight?No — API only Yes — self-hostable
Modalitiestext, image, code text, image, code
SWE-Bench Verified79.6% Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Best value in the Claude family

Claude Sonnet 4.6

Mistral Medium 3.5 is comparatively weak here — below the absolute frontier — a value/efficiency pick, not a flagship-beater

Everyday professional work

Claude Sonnet 4.6

Opus-class quality at lower cost; superseded as the default Sonnet by Claude Sonnet 5 (June 2026) — and it carries the larger 1M context.

Long-document analysis

Claude Sonnet 4.6

Its 1M window holds about 3.9× more than Mistral Medium 3.5's 256K in a single prompt.

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

Mistral Medium 3.5

At $1.5/$7.5 per 1M tokens it undercuts Claude Sonnet 4.6 ($3/$15 per 1M tokens), and that gap compounds at volume.

128B dense open-weight model — self-hostable

Mistral Medium 3.5

Open weights make this possible at all — Claude Sonnet 4.6 is API-only, so it cannot leave the vendor's servers.

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 runs cheaper at $1.5/$7.5 per 1M tokens.

Lowest cost at scale

Mistral Medium 3.5

At $1.5/$7.5 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Largest single-prompt input

Claude Sonnet 4.6

Its 1M window is about 3.9× larger than Mistral Medium 3.5's 256K, fitting roughly 1,500 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

Mistral Medium 3.5

At $1.5/$7.5 per 1M tokens it undercuts Claude Sonnet 4.6, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

Claude Sonnet 4.6

Larger 1M window fits more in one prompt.

A team with data-privacy or self-hosting needs

Mistral Medium 3.5

Open weights let you run it on your own hardware; Claude Sonnet 4.6 is API-only.

Anyone whose priority is best value in the claude family

Claude Sonnet 4.6

It is specifically built for that.

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

Mistral Medium 3.5

That is its strongest area.

An enterprise with regional data-residency rules

Claude Sonnet 4.6 or Mistral Medium 3.5

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

Claude Sonnet 4.6: where it fits

Opus-class quality at lower cost; superseded as the default Sonnet by Claude Sonnet 5 (June 2026). Released February 17, 2026 by Anthropic, it is built for best value in the Claude family, everyday professional work, long-document analysis, and coding at lower cost than Opus.

Its trade-offs are real: trails Opus on the hardest agentic tasks, and not an open-weight option. At $3 in / $15 out per million tokens, it sits in the mid price band.

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: 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.

The bottom line for this matchup

The defining split here is open vs. closed. Mistral Medium 3.5 gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. Claude Sonnet 4.6 gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.

Want both Claude Sonnet 4.6 and Mistral Medium 3.5 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 Claude Sonnet 4.6 or Mistral Medium 3.5 better for coding?

Public SWE-Bench figures are not available for Mistral Medium 3.5, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.6 leans toward best value in the claude family while Mistral Medium 3.5 leans toward strong intelligence-for-size — artificial analysis intelligence index 30, near the top of its price tier, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, Claude Sonnet 4.6 or Mistral Medium 3.5?

Mistral Medium 3.5 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while Claude Sonnet 4.6 is API-metered at $3/$15 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.

Which has the bigger context window?

Claude Sonnet 4.6 — 1M vs 256K, about 3.9× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both Claude Sonnet 4.6 and Mistral Medium 3.5 together?

Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.6, Mistral Medium 3.5 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, Claude Sonnet 4.6 or Mistral Medium 3.5?

Mistral Medium 3.5 — released April 29, 2026, about 2 months after Claude Sonnet 4.6.

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.