LLM Reference

GPT-5.4 vs Mistral Magistral Small 2509

GPT-5.4 (2026) and Mistral Magistral Small 2509 (2025) are frontier reasoning models from OpenAI and MistralAI. GPT-5.4 ships a 1.05m-token context window, while Mistral Magistral Small 2509 ships a not-yet-sourced context window. On pricing, GPT-5.4 ranges from $2.50 to $5/1M 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 is safer overall; choose Mistral Magistral Small 2509 when provider fit matters.

Decision scorecard

Local evidence first
SignalGPT-5.4Mistral Magistral Small 2509
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsprovider-routed production
Decision fitCoding, RAG, and AgentsGeneral
Context window1.05m
Cheapest output$15/1M tokens$1.50/1M tokens
Provider routes4 tracked2 tracked
Shared benchmarks0 shared0 shared

Decision tradeoffs

Choose GPT-5.4 when...
  • GPT-5.4 has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • GPT-5.4 has broader tracked provider coverage for fallback and route flexibility.
  • GPT-5.4 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
  • Local decision data tags GPT-5.4 for Coding, RAG, and Agents.
Choose Mistral Magistral Small 2509 when...
  • 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.

Lower estimate Mistral Magistral Small 2509

GPT-5.4

$5,750

Cheapest tracked route/tier: OpenAI API

Mistral Magistral Small 2509

$775

Cheapest tracked route/tier: AWS Bedrock

Estimated monthly gap: $4,975. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

GPT-5.4 -> Mistral Magistral Small 2509
  • Provider overlap exists on AWS Bedrock and Vercel AI Gateway; start route-level A/B tests there.
  • Mistral Magistral Small 2509 is $13.50/1M 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.
Mistral Magistral Small 2509 -> GPT-5.4
  • Provider overlap exists on Vercel AI Gateway and AWS Bedrock; start route-level A/B tests there.
  • GPT-5.4 is $13.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • GPT-5.4 adds Vision, Multimodal, and Reasoning in local capability data.

Specs

Specification
Released2026-03-052025-09-01
Context window1.05m
Parameters24B
ArchitectureDecoder Only-
LicenseProprietaryApache 2.0OSI-approved
OpennessProprietaryOpen source
WeightsNot releasedUnknown
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: permitted
Knowledge cutoff2025-08-

Pricing and availability

Pricing attributeGPT-5.4Mistral Magistral Small 2509
Input price
0-272,000t
$2.50/1M tokens
272,000t+
$5/1M tokens
$0.50/1M tokens
Output price
0-272,000t
$15/1M tokens
272,000t+
$22.50/1M tokens
$1.50/1M tokens
Providers

Capabilities

CapabilityGPT-5.4Mistral Magistral Small 2509
VisionYesNo
MultimodalYesNo
ReasoningYesNo
JSON / Tool useYesNo
Structured outputsYesNo
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

No shared benchmark scores are currently available for this pair.

Continue comparing

Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.