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GPT-5.5 Pro

OpenAI · GPT-5

Premium GPT-5.5 route for the hardest ChatGPT reasoning, research, and professional workflows.

Part of GPT family · Other versions: GPT-5.5 , GPT-Rosalind , GPT-5.4 mini , GPT-5.4 nano , GPT-5.4-Pro , GPT-5.4 , GPT-5.3 , GPT-5.3-Codex , GPT-5.2-Codex , GPT-5.2-Pro , GPT-5.2 , GPT-5-Codex , GPT-5 mini , GPT-5 , GPT-5 nano , GPT-4.1 , GPT-4o mini Transcribe , GPT-4o mini TTS , GPT-4o Transcribe , GPT-4o mini , GPT-4o
Type
language
Context
1M tokens
Max Output
128K tokens
Status
current
Input
$30/1M tok
Output
$180/1M tok
API Access
Yes
License
proprietary
frontier reasoning high-accuracy coding analysis tool-use research long-context
Released April 2026 · Updated April 26, 2026

Overview

Freshness note: Model capabilities, limits, and availability can change quickly. This profile is a point-in-time snapshot last verified on April 26, 2026.

GPT-5.5 Pro is the higher-compute member of OpenAI’s GPT-5.5 release. It launched on April 23, 2026 for Pro, Business, and Enterprise users in ChatGPT, and OpenAI now lists gpt-5.5-pro in the API model docs. OpenAI positions it as the highest-accuracy GPT-5.5 option for difficult professional work, long-running reasoning, research, and high-stakes synthesis.

This is not the model to use casually for every task. It is the escalation lane when the cost of a weak answer is higher than the cost and latency of a premium reasoning pass.

Capabilities

GPT-5.5 Pro is designed for harder questions and more demanding work than standard GPT-5.5 Thinking. OpenAI’s launch materials emphasize business, legal, education, data science, scientific research, manuscript critique, technical argument review, and complex analysis over large files or web context.

The main value is deeper test-time compute over the same underlying GPT-5.5 model. In practice, that should matter most when the answer needs stronger structure, better checking, and fewer missing constraints rather than just faster output.

Technical Details

OpenAI’s system card says GPT-5.5 Pro uses the same underlying model as GPT-5.5 with a setting that uses parallel test-time compute. The system card generally treats GPT-5.5 safety results as strong proxies for GPT-5.5 Pro, while still evaluating Pro separately where extra compute could materially change risk.

OpenAI’s API docs list gpt-5.5-pro with a 1,050,000-token context window and 128,000-token maximum output. In current ChatGPT product surfaces, GPT-5.5 Pro access is plan-gated and has product-specific tool limitations. OpenAI’s help article notes that Apps, Memory, Canvas, and image generation are not available with Pro.

Pricing & Access

GPT-5.5 Pro is available in ChatGPT for Pro, Business, and Enterprise users, and OpenAI’s API docs now list gpt-5.5-pro for developer use through the Responses API.

Published API pricing for gpt-5.5-pro is:

  • Input: $30.00 per 1M tokens
  • Output: $180.00 per 1M tokens

Best Use Cases

Use GPT-5.5 Pro for second-pass review, executive-ready memos, difficult architecture analysis, legal or policy synthesis with human review, scientific research support, and complex data-science reasoning. It is especially appropriate after a cheaper model has already narrowed the problem.

Avoid using it as a default chat model for routine drafting, simple coding, extraction, or support triage. The economics only make sense when the answer quality delta matters.

Comparisons

  • GPT-5.5 (OpenAI): Better default for hard agentic work where Pro-level spend is not justified.
  • GPT-5.4-Pro (OpenAI): Previous OpenAI Pro escalation tier, now superseded in product positioning by GPT-5.5 Pro.
  • Claude Opus 4.7 (Anthropic): Natural cross-vendor comparison for premium reasoning, coding, and long-horizon work.
  • Gemini 3.1 Pro Preview (Google): Preview alternative when Google-native multimodal and long-context integrations matter.