OpenAI: 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... 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 Extremely expensive at $30/$180 per 1M tokens Slower inference than standard GPT-5.5 Overkill for simple tasks where cheaper models suffice Deep research and complex analysis High-stakes agentic coding and codebase work Long-horizon multi-step reasoning tasks Enterprise-grade production agents
Specifications
| Lab | OpenAI |
|---|---|
| Context window | 1,050,000 |
| Input price | $30.00/1M |
| Output price | $180.00/1M |
| Release | 2026-04-01 00:00:00 |
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 2026-04-01 00:00:00. It currently appears in the Overall category on LMRank. It supports Image, 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.