Model comparison
GPT-5.5 Pro vs Mistral Small 4
Compare GPT-5.5 Pro vs Mistral Small 4 API pricing: input/output token costs, cache pricing, context windows, workload estimates, and routing fit.
GPT-5.5 Pro
openai · gpt-5.5-pro
- Input
- $30
- Output
- $180
- Context
- 1.1M
Mistral Small 4
mistral · mistral/mistral-small-2603
- Input
- $0.15
- Output
- $0.6
- Context
- 256K
Quick take
Mistral Small 4 has the lower input price at $0.15 per 1M input tokens. Mistral Small 4 is cheaper for the example blended workload below. GPT-5.5 Pro has the larger context window at 1.1M tokens.
Choose GPT-5.5 Pro if...
- GPT-5.5 Pro is safer for long documents, repository analysis, and RAG prompts because it has the larger context window.
- GPT-5.5 Pro gives more room for long generated answers, reports, or code output.
Choose Mistral Small 4 if...
- Mistral Small 4 is the better default for cost-sensitive traffic and repeated high-volume calls.
- Mistral Small 4 is stronger when the same large prompt or document is reused because it supports prompt caching.
Example workload cost
Estimates use input tokens plus 20% output tokens. They exclude provider discounts, cache hits, and tool/search surcharges.
| Workload | GPT-5.5 Pro | Mistral Small 4 | Cheaper |
|---|---|---|---|
| 1M input + 200K output | $66.00 | $0.27 | Mistral Small 4 |
| 10M input + 2M output | $660.00 | $2.70 | Mistral Small 4 |
| 100M input + 20M output | $6,600.00 | $27.00 | Mistral Small 4 |
Context, output, and capability fit
GPT-5.5 Pro provides the larger context window. Check max output separately when the task needs long reports, code generation, or full-document rewrites.
- GPT-5.5 Pro max output
- 128K
- Mistral Small 4 max output
- n/a
- GPT-5.5 Pro features
- function calling, vision
- Mistral Small 4 features
- prompt caching, function calling, vision
Risk notes for GPT-5.5 Pro
- High output price: cap max tokens for verbose generation workloads.
- No prompt caching in this snapshot: repeated long-context calls may be more expensive.
Risk notes for Mistral Small 4
- No major capability risk is flagged in this snapshot, but provider pages should still be verified before production routing.
Routing tags
frontierpremiumreasoningcodingagentslong-contextmultimodalragbudgetopen-weightenterpriselocal-open