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.
Specifications
| Lab | OpenAI |
|---|---|
| Context window | 1.1M tokens |
| Input price | $30.00/1M |
| Output price | $180.00/1M |
| Release | Apr 2026 |
Strengths
- Unmatched deep reasoning for complex high-stakes workloads
- 1M+ token context window with image input support
- Excels at long-horizon agents and multi-step coding
- Precise execution across agentic workflows
Weaknesses
- Extremely expensive at $30/$180 per 1M tokens
- Slower inference than standard GPT-5.5
- Overkill for simple tasks where cheaper models suffice
Best for
- Deep research and complex analysis
- High-stakes agentic coding and codebase work
- Long-horizon multi-step reasoning tasks
- Enterprise-grade production agents
In Depth: GPT-5.5 Pro
Summary
GPT-5.5 Pro is an AI model from OpenAI.
Released in Apr 2026. It currently appears in the Overall category on LMRank. It takes image and text input and produces text output, with a context window of 1.1M tokens. Input pricing is $30.00 per 1M tokens and output is $180.00 per 1M tokens on OpenRouter.