GPT-5.4 Mini vs Mistral Magistral Small 2509
GPT-5.4 Mini (2026) and Mistral Magistral Small 2509 (2025) are frontier reasoning models from OpenAI and MistralAI. GPT-5.4 Mini ships a 400K-token context window, while Mistral Magistral Small 2509 ships a not-yet-sourced context window. On pricing, Mistral Magistral Small 2509 costs $0.5/1M input tokens versus $0.75/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Mistral Magistral Small 2509 is ~50% cheaper at $0.5/1M; pay for GPT-5.4 Mini only for coding workflow support.
Decision scorecard
Local evidence first| Signal | GPT-5.4 Mini | Mistral Magistral Small 2509 |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | General |
| Context window | 400K | — |
| Cheapest output | $4.5/1M tokens | $1.5/1M tokens |
| Provider routes | 2 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- GPT-5.4 Mini has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.4 Mini has broader tracked provider coverage for fallback and procurement flexibility.
- GPT-5.4 Mini uniquely exposes Multimodal, Reasoning, and Function calling in local model data.
- Local decision data tags GPT-5.4 Mini for Coding, RAG, and Agents.
- Mistral Magistral Small 2509 has the lower cheapest tracked output price at $1.5/1M tokens.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
GPT-5.4 Mini
$1,725
Cheapest tracked route: OpenAI API
Mistral Magistral Small 2509
$775
Cheapest tracked route: AWS Bedrock
Estimated monthly gap: $950. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for GPT-5.4 Mini and Mistral Magistral Small 2509; plan for SDK, billing, or endpoint changes.
- Mistral Magistral Small 2509 is $3/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Multimodal, Reasoning, and Function calling before moving production traffic.
- No overlapping tracked provider route is sourced for Mistral Magistral Small 2509 and GPT-5.4 Mini; plan for SDK, billing, or endpoint changes.
- GPT-5.4 Mini is $3/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.4 Mini adds Multimodal, Reasoning, and Function calling in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-03-05 | 2025-09-01 |
| Context window | 400K | — |
| Parameters | — | — |
| Architecture | decoder only | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2025-08 | - |
Pricing and availability
| Pricing attribute | GPT-5.4 Mini | Mistral Magistral Small 2509 |
|---|---|---|
| Input price | $0.75/1M tokens | $0.5/1M tokens |
| Output price | $4.5/1M tokens | $1.5/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.4 Mini | Mistral Magistral Small 2509 |
|---|---|---|
| Vision | No | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | Yes | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on multimodal input: GPT-5.4 Mini, reasoning mode: GPT-5.4 Mini, function calling: GPT-5.4 Mini, tool use: GPT-5.4 Mini, structured outputs: GPT-5.4 Mini, and code execution: GPT-5.4 Mini. 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, GPT-5.4 Mini lists $0.75/1M input and $4.5/1M output tokens, while Mistral Magistral Small 2509 lists $0.5/1M input and $1.5/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Mistral Magistral Small 2509 lower by about $1.07 per million blended tokens. Availability is 2 providers versus 1, so concentration risk also matters.
Choose GPT-5.4 Mini when coding workflow support and broader provider choice are central to the workload. Choose Mistral Magistral Small 2509 when provider fit and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions.
FAQ
Which is cheaper, GPT-5.4 Mini or Mistral Magistral Small 2509?
Mistral Magistral Small 2509 is cheaper on tracked token pricing. GPT-5.4 Mini costs $0.75/1M input and $4.5/1M output tokens. Mistral Magistral Small 2509 costs $0.5/1M input and $1.5/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is GPT-5.4 Mini or Mistral Magistral Small 2509 open source?
GPT-5.4 Mini is listed under Proprietary. Mistral Magistral Small 2509 is listed under Proprietary. 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 multimodal input, GPT-5.4 Mini or Mistral Magistral Small 2509?
GPT-5.4 Mini 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, GPT-5.4 Mini or Mistral Magistral Small 2509?
GPT-5.4 Mini 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.
Which is better for function calling, GPT-5.4 Mini or Mistral Magistral Small 2509?
GPT-5.4 Mini has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GPT-5.4 Mini and Mistral Magistral Small 2509?
GPT-5.4 Mini is available on OpenAI API and OpenRouter. Mistral Magistral Small 2509 is available on AWS Bedrock. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-11. Data sourced from public model cards and provider documentation.