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 text and image inputs, and is designed for long-horizon problem solving, agentic coding, and precise execution across multi-step workflows.
Modalities
Context
1M
Released
Apr 24, 2026
Knowledge Cutoff
Dec 2025
Token volume and request traffic to this model over time.
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 text and image inputs, and is designed for long-horizon problem solving, agentic coding, and precise execution across multi-step workflows.
GPT-5.5 Pro has a 1,050,000 token context window.
GPT-5.5 Pro accepts files such as PDFs, images and text as input and returns text.
GPT-5.6 Luna Pro, GPT-5.6 Luna, GPT-5.6 Terra Pro and 54 more are other text models from OpenAI.
GPT-5.5 Pro was released on April 24, 2026. Its knowledge cutoff is December 1, 2025.