GPT-5.5 is OpenAI’s frontier model designed for complex professional workloads, building on GPT-5.4 with stronger reasoning, higher reliability, and improved token efficiency on hard tasks. It features a 1M+ token context window (922K input, 128K output) with support for text and image inputs, enabling large-scale reasoning, coding, and multimodal workflows within a single system.
Modalities
In / Out Price
High
$5 / $30per 1M
Context
High
1M
Released
Apr 24, 2026
Knowledge Cutoff
Dec 2025