GPT-5.5 Pro (Reasoning)

by OpenAI

GPT-5.5 Pro (Reasoning) is a reasoning model from OpenAI, released on April 23, 2026. It has a 1.1M-token context window and can generate up to 128K output tokens. API pricing is $30 per 1M input tokens and $180 per 1M output tokens. It ranks #29 of 220 models by Intelligence Score with a score of 45.5.

GPT-5.5 Pro is the Pro variant of GPT-5.5, designed for the hardest questions and highest-accuracy work. It scales reasoning further than GPT-5.5 with significantly more comprehensive, well-structured, and accurate responses, with especially strong performance in business, legal, education, science, and data analysis. Priced at $30/1M input and $180/1M output tokens with a 1M context window.

Key specs

ProviderOpenAI
Release date2026-04-23
Licenseproprietary
Context window1.1M tokens
Max output128K tokens
Input price$30 / 1M tokens
Output price$180 / 1M tokens
Intelligence Score45.5

Quick answers

What is the context window of GPT-5.5 Pro (Reasoning)?

GPT-5.5 Pro (Reasoning) has a context window of 1.1M tokens, with a maximum output of 128K tokens per response.

How much does GPT-5.5 Pro (Reasoning) cost?

GPT-5.5 Pro (Reasoning) costs $30 per 1M input tokens and $180 per 1M output tokens through the API.

Is GPT-5.5 Pro (Reasoning) open source?

No. GPT-5.5 Pro (Reasoning) is a proprietary model from OpenAI (proprietary license).

When was GPT-5.5 Pro (Reasoning) released?

OpenAI released GPT-5.5 Pro (Reasoning) on April 23, 2026.

How does GPT-5.5 Pro (Reasoning) compare to Claude Opus 5.5 (Reasoning)?

GPT-5.5 Pro (Reasoning) scores 45.5 on the Intelligence Score versus 60.5 for Claude Opus 5.5 (Reasoning), the current #1. Input pricing is $30 vs $4 per 1M tokens.

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