Model by OpenAI

GPT-5.5

GPT-5.5 is OpenAI's previous flagship, and it suits teams that pinned it for professional and agentic work and have not yet moved to the 6 series.

Checked 2026-11-05

GPT-5.5 is OpenAI's previous flagship, and it suits teams that pinned it for professional and agentic work and have not yet moved to the 6 series. OpenAI's model page lists 1,050,000 tokens of context, 128,000 tokens of output, and a knowledge cutoff of 1 December 2025. The default snapshot is dated 23 April 2026, and OpenRouter listed the model on 24 April 2026. Price is $5 per million input tokens, $0.50 per million cached input tokens and $30 per million output tokens. Prompts over 272,000 input tokens cost twice as much for input and one and a half times as much for output across the full session, and regional processing endpoints add 10 percent. You reach it through Chat Completions, Responses and Batch. Realtime, fine-tuning and embeddings are not supported. The page shows no lifecycle status, and GPT-5.5 does not appear on OpenAI's deprecations page today, but check it before building long-term plans. Its $30 output rate is well above Sol's promotional $20, which is the main reason to move. We would keep it only for pinned pipelines. Figures come from OpenAI's model and deprecations pages and OpenRouter. We have not run it ourselves.

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Questions

What is the context window of GPT-5.5?

1,050,000 tokens, with up to 128,000 tokens of output.

How much does GPT-5.5 cost?

$5 per million input tokens and $30 per million output tokens, checked 31 October 2026.

Can I run GPT-5.5 on my own hardware?

No. The weights are not published, so you use it through the maker's API or a hosting provider.

Who makes GPT-5.5?

OpenAI makes it, and released it on 24 April 2026.

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