OpenAI · OpenAI (GPT / ChatGPT)
GPT-5.5 Pro
ActiveReleased 2 months ago· Apr 23, 2026Multimodal model
Maximum-reasoning-depth variant of GPT-5.5 for research-grade problems ($30/$180 per 1M).
- API string
- gpt-5.5-pro
- Context window
- 1M ctx
- Knowledge cutoff
- Jan 1, 2026
- Tier
- Reasoning
- Released
- Apr 23, 2026
Release & change timeline
1 event- Release
GPT-5.5 Pro released
Maximum-reasoning-depth variant at $30/$180 per 1M tokens.
Part of the OpenAI (GPT / ChatGPT) version timeline. Catch Me Up — everything that changed across AI & smart home ↗