OpenAI LLM Big Closed weights

GPT-5.5

203 days since OpenAI announced it · 23 Apr 2026

GPT-5.5 is a closed-weights LLM from OpenAI, announced 23 Apr 2026. It costs $5 per 1M input tokens and $30 per 1M output tokens. Its context window is 1.05M tokens.

Input: $5; per 1M tokens
Cache write: —; per 1M tokens
Cache read: $0.50; per 1M tokens
Output: $30; per 1M tokens
Context window: 1.05M; tokens
Parameters: —; not disclosed

Announcement: openai.com/index/introducing-gpt-5-5
Docs: developers.openai.com/api/docs/models/gpt-5.5

Our coverage

We haven’t written about GPT-5.5 yet.

OpenAI · Big

closed weights

A new one every ~66 days — due now.

GPT-6 Astra +133d 3 Sep 2026
GPT-5.5 +49d 23 Apr 2026
GPT-5.4 +84d 5 Mar 2026
GPT-5.2 +28d 11 Dec 2025
GPT-5.1 +98d 13 Nov 2025
GPT-5 7 Aug 2025