Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick Mistral Medium 3 for strong cost-to-capability at $0.40/$2.00 or general reasoning, coding and multimodal tasks. On a tight budget at scale, Mistral Medium 3 is the value pick.
Claude Sonnet 4.5 (Anthropic, US) and Mistral Medium 3 (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 Claude Sonnet 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Mistral Medium 3 is mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences
Price: Mistral Medium 3 is about 7.5× cheaper on input ($0.4/$2 per 1M tokens vs $3/$15 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
Context window: Claude Sonnet 4.5 holds 1.6× more — 200K (~300 pages) vs 128K (~192 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
Recency: Claude Sonnet 4.5 is the newer model by about 5 months (released September 29, 2025), usually meaning fresher training data and capabilities.
Ecosystem: this is a US-vs-France matchup — they differ in pricing philosophy, data-residency options, and tooling ecosystems, not only benchmarks.
Specifications
Spec
Claude Sonnet 4.5
Mistral Medium 3
Provider
Anthropic (US)
Mistral AI (France)
Released
September 29, 2025
May 7, 2025
Context window
200K (~300 pages)
128K (~192 pages)
Price (in/out)
$3/$15 per 1M tokens
$0.4/$2 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, code
SWE-Bench Verified
77.2%
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — Mistral Medium 3 is comparatively weak here — no published SWE-Bench Verified score
Computer use and GUI automation (61.4% OSWorld at launch): Claude Sonnet 4.5 — September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded — and it carries the larger 200K context.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks: Claude Sonnet 4.5 — Its 200K window holds about 1.6× more than Mistral Medium 3's 128K in a single prompt.
Strong cost-to-capability at $0.40/$2.00: Mistral Medium 3 — At $0.4/$2 per 1M tokens it undercuts Claude Sonnet 4.5 ($3/$15 per 1M tokens), and that gap compounds at volume.
General reasoning, coding and multimodal tasks: Mistral Medium 3 — Mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier — and it runs cheaper at $0.4/$2 per 1M tokens.
Efficient mid-tier deployment for production workloads: Mistral Medium 3 — Mistral Medium 3 lists efficient mid-tier deployment for production workloads among its strengths; Claude Sonnet 4.5 does not.
Lowest cost at scale: Mistral Medium 3 — At $0.4/$2 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 4.5 — Its 200K window is about 1.6× larger than Mistral Medium 3's 128K, fitting roughly 300 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume: Mistral Medium 3 — At $0.4/$2 per 1M tokens it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases: Claude Sonnet 4.5 — Larger 200K window fits more in one prompt.
Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch: Claude Sonnet 4.5 — It is specifically built for that.
Anyone whose priority is strong cost-to-capability at $0.40/$2.00: Mistral Medium 3 — That is its strongest area.
An enterprise with regional data-residency rules: Claude Sonnet 4.5 or Mistral Medium 3 — Origin (US vs France) affects where data is processed and which compliance regime applies — check the provider's terms for your region.
Claude Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 out per million tokens, it sits in the mid price band.
Mistral Medium 3: where it fits
Mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier. Released May 7, 2025 by Mistral AI, it is built for strong cost-to-capability at $0.40/$2.00, general reasoning, coding and multimodal tasks, efficient mid-tier deployment for production workloads, and text and image input.
Its trade-offs: a 128K context — smaller than the 1M-window flagships here, no published SWE-Bench Verified score, a mid-tier model, not a frontier reasoner, and proprietary, unlike Mistral's open-weight releases. At $0.4 in / $2 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." Claude Sonnet 4.5 (US) and Mistral Medium 3 (France) differ on pricing philosophy, data-residency, and tooling as much as on raw scores. Mistral Medium 3 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.
Frequently asked questions
Is Claude Sonnet 4.5 or Mistral Medium 3 better for coding?
Public SWE-Bench figures are not available for Mistral Medium 3, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch while Mistral Medium 3 leans toward strong cost-to-capability at $0.40/$2.00, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 4.5 or Mistral Medium 3?
Mistral Medium 3 is cheaper — $3/$15 per 1M tokens vs $0.4/$2 per 1M tokens, roughly 7.5× apart on input.
Which has the bigger context window?
Claude Sonnet 4.5 — 200K vs 128K, about 1.6× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 4.5 and Mistral Medium 3 together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, Mistral Medium 3 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 4.5 or Mistral Medium 3?
Claude Sonnet 4.5 — released September 29, 2025, about 5 months after Mistral Medium 3.
Claude Sonnet 4.5 vs Mistral Medium 3
Anthropic · US | Mistral AI · France · Updated June 2026
Quick verdict
Pick Claude Sonnet 4.5 for agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch or computer use and gui automation (61.4% osworld at launch). Pick Mistral Medium 3 for strong cost-to-capability at $0.40/$2.00 or general reasoning, coding and multimodal tasks. On a tight budget at scale, Mistral Medium 3 is the value pick.
Claude Sonnet 4.5 (Anthropic, US) and Mistral Medium 3 (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 4.5 is september 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Mistral Medium 3 is mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier. They diverge most on price and context window — each quantified below from the models' real specs.
Key differences at a glance
▸Price: Mistral Medium 3 is about 7.5× cheaper on input ($0.4/$2 per 1M tokens vs $3/$15 per 1M tokens) — a large enough gap that at scale it can be the single biggest line item in the decision.
▸Context window: Claude Sonnet 4.5 holds 1.6× more — 200K (~300 pages) vs 128K (~192 pages). But effective recall usually fades long before the advertised ceiling, so the bigger number only helps if the model reasons over it.
▸Recency: Claude Sonnet 4.5 is the newer model by about 5 months (released September 29, 2025), usually meaning fresher training data and capabilities.
▸Ecosystem: this is a US-vs-France matchup — they differ in pricing philosophy, data-residency options, and tooling ecosystems, not only benchmarks.
Side-by-side specs
Spec
Claude Sonnet 4.5
Mistral Medium 3
Provider
Anthropic (US)
Mistral AI (France)
Released
September 29, 2025
May 7, 2025
Context window
200K (~300 pages)
128K (~192 pages)
Price (in/out)
$3/$15 per 1M tokens
$0.4/$2 per 1M tokens
Open weight?
No — API only
No — API only
Modalities
text, image, code
text, image, code
SWE-Bench Verified
77.2%
Not published
MRCR v2 @ 1M
Not published
Not published
Who wins what
Agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch
Claude Sonnet 4.5
Mistral Medium 3 is comparatively weak here — no published SWE-Bench Verified score
Computer use and GUI automation (61.4% OSWorld at launch)
Claude Sonnet 4.5
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded — and it carries the larger 200K context.
Long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks
Claude Sonnet 4.5
Its 200K window holds about 1.6× more than Mistral Medium 3's 128K in a single prompt.
Strong cost-to-capability at $0.40/$2.00
Mistral Medium 3
At $0.4/$2 per 1M tokens it undercuts Claude Sonnet 4.5 ($3/$15 per 1M tokens), and that gap compounds at volume.
General reasoning, coding and multimodal tasks
Mistral Medium 3
Mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier — and it runs cheaper at $0.4/$2 per 1M tokens.
Efficient mid-tier deployment for production workloads
Mistral Medium 3
Mistral Medium 3 lists efficient mid-tier deployment for production workloads among its strengths; Claude Sonnet 4.5 does not.
Lowest cost at scale
Mistral Medium 3
At $0.4/$2 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 4.5
Its 200K window is about 1.6× larger than Mistral Medium 3's 128K, fitting roughly 300 pages in one prompt.
Which should you pick?
A cost-sensitive startup shipping high volume
→ Mistral Medium 3
At $0.4/$2 per 1M tokens it undercuts Claude Sonnet 4.5, and on millions of tokens that margin decides the monthly bill.
Someone analysing very long documents or codebases
→ Claude Sonnet 4.5
Larger 200K window fits more in one prompt.
Anyone whose priority is agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch
→ Claude Sonnet 4.5
It is specifically built for that.
Anyone whose priority is strong cost-to-capability at $0.40/$2.00
→ Mistral Medium 3
That is its strongest area.
An enterprise with regional data-residency rules
→ Claude Sonnet 4.5 or Mistral Medium 3
Origin (US vs France) affects where data is processed and which compliance regime applies — check the provider's terms for your region.
Claude Sonnet 4.5: where it fits
September 2025's coding state of the art at $3/$15 — still supported, but 200K-capped and twice superseded. Released September 29, 2025 by Anthropic, it is built for agentic coding — 77.2% on SWE-Bench Verified, the best score any model had posted at its launch, computer use and GUI automation (61.4% OSWorld at launch), long-horizon autonomy — Anthropic reported 30+ hours of sustained focus on multi-step tasks, and tracking its own remaining token budget natively, which few models do.
Its trade-offs are real: superseded twice — Sonnet 4.6 and Sonnet 5 match or beat it at the same or lower price, capped at 200K since Anthropic retired its 1M beta in April 2026, while its successors ship 1M as standard, and missing the modern API surface: no adaptive thinking, no effort control, and half the max output of newer Sonnets. At $3 in / $15 out per million tokens, it sits in the mid price band.
Mistral Medium 3: where it fits
Mistral's mid-tier model at $0.40/$2.00 — efficient general capability with a 128K window, below the 1M-context frontier tier. Released May 7, 2025 by Mistral AI, it is built for strong cost-to-capability at $0.40/$2.00, general reasoning, coding and multimodal tasks, efficient mid-tier deployment for production workloads, and text and image input.
Its trade-offs: a 128K context — smaller than the 1M-window flagships here, no published SWE-Bench Verified score, a mid-tier model, not a frontier reasoner, and proprietary, unlike Mistral's open-weight releases. At $0.4 in / $2 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." Claude Sonnet 4.5 (US) and Mistral Medium 3 (France) differ on pricing philosophy, data-residency, and tooling as much as on raw scores. Mistral Medium 3 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 Claude Sonnet 4.5 and Mistral Medium 3 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.
Is Claude Sonnet 4.5 or Mistral Medium 3 better for coding?
Public SWE-Bench figures are not available for Mistral Medium 3, so the honest test is your own repository — run an identical real bug through both. By design, Claude Sonnet 4.5 leans toward agentic coding — 77.2% on swe-bench verified, the best score any model had posted at its launch while Mistral Medium 3 leans toward strong cost-to-capability at $0.40/$2.00, and that positioning usually predicts which feels better on your codebase.
Which is cheaper, Claude Sonnet 4.5 or Mistral Medium 3?
Mistral Medium 3 is cheaper — $3/$15 per 1M tokens vs $0.4/$2 per 1M tokens, roughly 7.5× apart on input.
Which has the bigger context window?
Claude Sonnet 4.5 — 200K vs 128K, about 1.6× larger. Useful only if the model actually reasons over the full window, which not all do.
Can I use both Claude Sonnet 4.5 and Mistral Medium 3 together?
Yes — a multi-model platform like LumiChats gives you Claude Sonnet 4.5, Mistral Medium 3 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 4.5 or Mistral Medium 3?
Claude Sonnet 4.5 — released September 29, 2025, about 5 months after Mistral Medium 3.
Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.