GPT-5.5 Pro
GPT-5.5 Pro is a variant of GPT-5.5 applying additional parallel test-time compute on harder questions, targeting higher-accuracy work in business, legal, scientific, and data-intensive domains.
Technical specification
Modalities
Capabilities
17Reasoning★
Reasoning
Multi-step reasoning★
Reasoning
Long context★
Reasoning
Coding★
Coding
Function Calling
Planning
Structured output★
Structured gen.
Audio understanding
Audio
Image understanding★
Vision
Video Understanding
Other
Chart understanding
Vision
Diagram reasoning
Reasoning
OCR★
Vision
Multilingual★
Language
Planning★
Planning
Streaming output
Reasoning
Interleaved Multimodal Input
Reasoning
Multimodal understanding★
Multimodality
Architecture and technologies
Core Architecture
1Form / Family
3Training Techniques
4Applications
API: $30.00 / 1M input tokens, $180.00 / 1M output tokens. No cached input discount. Available in the API via the Responses and Chat Completions endpoints, as well as Batch (50% off) and Priority (2.5x) processing tiers. In ChatGPT, available on Pro, Business, and Enterprise plans.
INPUT
$30.0000 / per 1M tokens
OUTPUT
$180.0000 / per 1M tokens
TOTAL
for 10K tokens
No cached input discount. Responses API only.
Security and enterprise
OpenAI rates the cyber and biological capabilities of GPT-5.5 models (including Pro) as High under its Preparedness Framework. The model underwent a full pre-release safety process, including targeted evaluations for advanced cyber and biological capabilities.