GPT-5.1 vs Mistral Medium 3.5
GPT-5.1 vs Mistral Medium 3.5: GPT-5.1 is cheaper for input-heavy usage ($1.25/M vs $1.50/M input tokens), while GPT-5.1 is better for long-context tasks (1,000,000 tokens).
Direct answer: choose GPT-5.1 for lower token spend and choose GPT-5.1 when your workload needs longer context.
Compare input and output token pricing, context windows, and monthly cost estimates on one page so you can pick the cheaper model fast.
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
GPT-5.1
Mistral Medium 3.5
Cost Differences
Mistral Medium 3.5 costs less than GPT-5.1
Quick Recommendation
Winner for direct API pricing: Mistral Medium 3.5. At the default workload, Mistral Medium 3.5 saves about $3.00/month ($36.50/year) versus GPT-5.1.
Feature Comparison
| Feature | GPT-5.1 | Mistral Medium 3.5 |
|---|---|---|
| Provider | OpenAI | Mistral AI |
| Input Price | $1.25/1M tokens | $1.50/1M tokens |
| Output Price | $10.00/1M tokens | $7.50/1M tokens |
| Context Window | 1,000,000 tokens | 256,000 tokens |
| Max Output | 131,072 tokens | 32,768 tokens |
| Category | flagship | flagship |
| Capabilities | textvisionaudiocodereasoning | textvisioncodereasoning |
| Release Date | 11/12/2025 | 4/29/2026 |
GPT-5.1 vs Mistral Medium 3.5: Which Should You Choose?
Choosing between GPT-5.1 and Mistral Medium 3.5 depends on your priorities: cost efficiency, context length, or raw capability. Mistral Medium 3.5 is the more affordable option at $1.50/1M input tokens. Meanwhile, GPT-5.1 offers a significantly larger context window at 1,000,000 tokens vs 256,000 for Mistral Medium 3.5.
These models come from different providers — OpenAI and Mistral AI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with OpenAI, switching to Mistral AIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
Both models are in the flagship category, making this a direct head-to-head comparison. At scale — say 10,000 requests per day — the cost difference adds up: Mistral Medium 3.5 would save you roughly $300.00/month compared to GPT-5.1. For startups and indie developers, that difference can be significant.
Output costs matter too. GPT-5.1 charges $10.00/1M output tokens vs $7.50 for Mistral Medium 3.5. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Mistral Medium 3.5 has the edge here at $7.50/1M output tokens.
Multimodal capabilities: Both models support vision (image understanding), so you can send images alongside text prompts with either option.
Best Use Cases
Choose GPT-5.1 when:
- • Budget is a primary concern
- • You need a larger context window (1,000,000 tokens)
- • You need more capabilities (audio)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using OpenAI's API ecosystem
Choose Mistral Medium 3.5 when:
- • You're already using Mistral AI's API ecosystem
Pros and Caveats at a Glance
GPT-5.1
- • Input pricing: $1.25/M tokens
- • Output pricing: $10.00/M tokens
- • Context window: 1,000,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Higher output cost than Mistral Medium 3.5
Mistral Medium 3.5
- • Input pricing: $1.50/M tokens
- • Output pricing: $7.50/M tokens
- • Context window: 256,000 tokens
- • Max output: 32,768 tokens
Watch out for
- • Higher input cost than GPT-5.1
- • Smaller context window than GPT-5.1
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
GPT-5.1 (OpenAI)
Mistral Medium 3.5 (Mistral AI)
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Sign Up for Mistral AI →Frequently Asked Questions
Which is cheaper, GPT-5.1 or Mistral Medium 3.5?▼
What is the context window difference between GPT-5.1 and Mistral Medium 3.5?▼
Which model is better for AI Agent / Agentic Workflows?▼
Which model has better overall pricing for heavy usage?▼
Where can I compare OpenAI and Mistral AI API pricing beyond this model matchup?▼
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