GPT-4o-mini vs GPT-5.5 Pro
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for GPT-4o-mini and GPT-5.5 Pro.
GPT-4o-mini
GPT-4o mini is OpenAI's newest model after [GPT-4 Omni](/models/openai/gpt-4o), supporting both text and image inputs with text outputs. As their most advanced small model, it is many multiples more affordable...
GPT-5.5 Pro
GPT-5.5 Pro is OpenAI’s high-capability model optimized for deep reasoning and accuracy on complex, high-stakes workloads. It features a 1M+ token context window (922K input, 128K output) with support for...
Technical Specifications
| Specification | GPT-4o-mini | GPT-5.5 Pro |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 128,000 tokens | 1,050,000 tokens |
| Agent Suitability | 82/100 | 98/100 |
| Time to First Token (TTFT) | 150 ms | 450 ms |
| Deployment Model | managed api | managed api |
| Production Stability | stable | beta |
| API Available | Yes | Yes |
| Released Date | 2024-07-18 | 2026-04-24 |
API Pricing Comparison
Input Price per Million Tokens
GPT-4o-mini
$0.15
GPT-5.5 Pro
$30.00
Output Price per Million Tokens
GPT-4o-mini
$0.60
GPT-5.5 Pro
$180.00
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
GPT-4o-mini Quirks & Gotchas
- ▸Ultra-low latency — best TTFT in the OpenAI lineup
- ▸Tool calling limited to single-step — not suitable for complex agentic pipelines
GPT-5.5 Pro Quirks & Gotchas
- ▸Best-in-class instruction following for complex agentic chains
- ▸Premium pricing — use GPT-5 for cost-sensitive workloads