Mistral Medium 3.5 vs o3
Mistral Medium 3.5 vs o3: Mistral Medium 3.5 is cheaper for input-heavy usage ($1.50/M vs $2.00/M input tokens), while o3 is better for long-context tasks (1,000,000 tokens).
Direct answer: choose Mistral Medium 3.5 for lower token spend and choose o3 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)
Mistral Medium 3.5
o3
Cost Differences
o3 costs more than Mistral Medium 3.5
Quick Recommendation
Winner for direct API pricing: Mistral Medium 3.5. At the default workload, Mistral Medium 3.5 saves about $2.25/month ($27.375/year) versus o3.
Feature Comparison
| Feature | Mistral Medium 3.5 | o3 |
|---|---|---|
| Provider | Mistral AI | OpenAI |
| Input Price | $1.50/1M tokens | $2.00/1M tokens |
| Output Price | $7.50/1M tokens | $8.00/1M tokens |
| Context Window | 256,000 tokens | 1,000,000 tokens |
| Max Output | 32,768 tokens | 131,072 tokens |
| Category | flagship | reasoning |
| Capabilities | textvisioncodereasoning | textreasoningvisioncode |
| Release Date | 4/29/2026 | 4/16/2025 |
Mistral Medium 3.5 vs o3: Which Should You Choose?
Choosing between Mistral Medium 3.5 and o3 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 — 25% cheaper than o3. Meanwhile, o3 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 — Mistral AI and OpenAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with Mistral AI, switching to OpenAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
These models target different tiers: Mistral Medium 3.5 is a flagship model while o3 is reasoning. This means they're optimized for different workloads. Mistral Medium 3.5 is built for complex tasks that require deeper reasoning, while o3 offers better value for routine operations.
Output costs matter too. Mistral Medium 3.5 charges $7.50/1M output tokens vs $8.00 for o3. 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 Mistral Medium 3.5 when:
- • Budget is a primary concern
- • You're already using Mistral AI's API ecosystem
Choose o3 when:
- • You need a larger context window (1,000,000 tokens)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using OpenAI's API ecosystem
Pros and Caveats at a Glance
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
- • Smaller context window than o3
o3
- • Input pricing: $2.00/M tokens
- • Output pricing: $8.00/M tokens
- • Context window: 1,000,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Higher input cost than Mistral Medium 3.5
- • Higher output cost than Mistral Medium 3.5
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
Mistral Medium 3.5 (Mistral AI)
o3 (OpenAI)
Start using Mistral Medium 3.5 today
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Sign Up for OpenAI →Frequently Asked Questions
Which is cheaper, Mistral Medium 3.5 or o3?▼
What is the context window difference between Mistral Medium 3.5 and o3?▼
Which model is better for AI Agent / Agentic Workflows?▼
Which model has better overall pricing for heavy usage?▼
Where can I compare Mistral AI and OpenAI API pricing beyond this model matchup?▼
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