Mistral Magistral Small 2509 vs Mistral Medium 3.5
Mistral Magistral Small 2509 (2025) and Mistral Medium 3.5 (2026) are frontier reasoning models from MistralAI. Mistral Magistral Small 2509 ships a not-yet-sourced context window, while Mistral Medium 3.5 ships a 262k-token context window. On pricing, Mistral Magistral Small 2509 costs $0.50/1M input tokens versus $1.50/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Mistral Magistral Small 2509 is ~200% cheaper at $0.50/1M; pay for Mistral Medium 3.5 only for reasoning depth.
Decision scorecard
Local evidence first| Signal | Mistral Magistral Small 2509 | Mistral Medium 3.5 |
|---|---|---|
| Best for | provider-routed production | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | General | Coding, RAG, and Agents |
| Context window | — | 262k |
| Cheapest output | $1.50/1M tokens | $7.50/1M tokens |
| Provider routes | 2 tracked | 3 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Mistral Magistral Small 2509 has the lower cheapest tracked output price at $1.50/1M tokens.
- Mistral Medium 3.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Mistral Medium 3.5 has broader tracked provider coverage for fallback and procurement flexibility.
- Mistral Medium 3.5 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Mistral Medium 3.5 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Mistral Magistral Small 2509
$775
Cheapest tracked route/tier: AWS Bedrock
Mistral Medium 3.5
$3,075
Cheapest tracked route/tier: Mistral AI Studio
Estimated monthly gap: $2,300. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- Mistral Medium 3.5 is $6/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Mistral Medium 3.5 adds Vision, Multimodal, and Reasoning in local capability data.
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- Mistral Magistral Small 2509 is $6/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-01 | 2026-04-29 |
| Context window | — | 262k |
| Parameters | 24B | 128B |
| Architecture | - | Decoder Only |
| License | Apache 2.0OSI-approved | Mistral Modified MIT License |
| Openness | Open source | Open weights |
| Weights | Unknown | Available |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: permitted | Commercial use: conditional |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Mistral Magistral Small 2509 | Mistral Medium 3.5 |
|---|---|---|
| Input price | $0.50/1M tokens | $1.50/1M tokens |
| Output price | $1.50/1M tokens | $7.50/1M tokens |
| Providers |
Capabilities
| Capability | Mistral Magistral Small 2509 | Mistral Medium 3.5 |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | No | Yes |
| Function calling | No | Yes |
| Tool use | No | Yes |
| Structured outputs | No | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
Deep dive
The capability footprint differs most on vision: Mistral Medium 3.5, multimodal input: Mistral Medium 3.5, reasoning mode: Mistral Medium 3.5, function calling: Mistral Medium 3.5, tool use: Mistral Medium 3.5, and structured outputs: Mistral Medium 3.5. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Mistral Magistral Small 2509 lists $0.50/1M input and $1.50/1M output tokens on the cheapest tracked provider, while Mistral Medium 3.5 lists $1.50/1M input and $7.50/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Mistral Magistral Small 2509 lower by about $2.50 per million blended tokens. Availability is 2 providers versus 3, so concentration risk also matters.
Choose Mistral Magistral Small 2509 when provider fit and lower input-token cost are central to the workload. Choose Mistral Medium 3.5 when reasoning depth and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which is cheaper, Mistral Magistral Small 2509 or Mistral Medium 3.5?
Mistral Magistral Small 2509 is cheaper on tracked token pricing. Mistral Magistral Small 2509 costs $0.50/1M input and $1.50/1M output tokens. Mistral Medium 3.5 costs $1.50/1M input and $7.50/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Mistral Magistral Small 2509 or Mistral Medium 3.5 open source?
Mistral Magistral Small 2509 is listed under Apache 2.0. Mistral Medium 3.5 is listed under Mistral Modified MIT License. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Mistral Magistral Small 2509 or Mistral Medium 3.5?
Mistral Medium 3.5 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Mistral Magistral Small 2509 or Mistral Medium 3.5?
Mistral Medium 3.5 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, Mistral Magistral Small 2509 or Mistral Medium 3.5?
Mistral Medium 3.5 has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Mistral Magistral Small 2509 and Mistral Medium 3.5?
Mistral Magistral Small 2509 is available on AWS Bedrock and Vercel AI Gateway. Mistral Medium 3.5 is available on Mistral AI Studio, OpenRouter, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.