GPT-5.4 Pro vs Mistral Magistral Small 2509
GPT-5.4 Pro (2026) and Mistral Magistral Small 2509 (2025) are frontier reasoning models from OpenAI and MistralAI. GPT-5.4 Pro ships a 1.05m-token context window, while Mistral Magistral Small 2509 ships a not-yet-sourced context window. On pricing, GPT-5.4 Pro ranges from $30 to $60/1M input tokens by tier; Mistral Magistral Small 2509 costs $0.50/1M input tokens. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
GPT-5.4 Pro is safer overall; choose Mistral Magistral Small 2509 when provider fit matters.
Decision scorecard
Local evidence first| Signal | GPT-5.4 Pro | Mistral Magistral Small 2509 |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | provider-routed production |
| Decision fit | Coding, RAG, and Agents | General |
| Context window | 1.05m | — |
| Cheapest output | $180/1M tokens | $1.50/1M tokens |
| Provider routes | 3 tracked | 2 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- GPT-5.4 Pro has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.4 Pro has broader tracked provider coverage for fallback and route flexibility.
- GPT-5.4 Pro uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags GPT-5.4 Pro for Coding, RAG, and Agents.
- Mistral Magistral Small 2509 has the lower cheapest tracked output price at $1.50/1M tokens.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
GPT-5.4 Pro
$69,000
Cheapest tracked route/tier: OpenRouter
Mistral Magistral Small 2509
$775
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $68,225. 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 Magistral Small 2509 is $179/1M 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.
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- GPT-5.4 Pro is $179/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- GPT-5.4 Pro adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-03-01 | 2025-09-01 |
| Context window | 1.05m | — |
| Parameters | — | 24B |
| Architecture | Decoder Only | - |
| License | Proprietary | Apache 2.0OSI-approved |
| Openness | Proprietary | Open source |
| Weights | Not released | Unknown |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | 2025-08 | - |
Pricing and availability
| Pricing attribute | GPT-5.4 Pro | Mistral Magistral Small 2509 |
|---|---|---|
| Input price |
| $0.50/1M tokens |
| Output price |
| $1.50/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.4 Pro | Mistral Magistral Small 2509 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| JSON / Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.