Skip to contentGPT-5.5 Pro
CurrentStale ·
The highest-capability GPT-5.5 variant, using more reasoning compute for the most difficult problems where cost and latency are secondary concerns.
profile normalized against the 88-model field
Context window· 1.05M of 10M11%
Max output· 128K of 384K33%
Affordability· $180.00 / Mtok out0%
Capability breadth· 2 of 1118%
Capability switches · 2 of 11
Reasoning mode
Tool / function use
Streaming
JSON mode
Structured outputs
Prompt caching
Fine-tuning
Web search
Code execution
Vision input
Audio input
Specifications
Every value carries a primary source and a verification date.
Pricing
Input $/Mtok$30.00 / Mtok
Output $/Mtok$180.00 / Mtok
Capabilities
Input modalitiesText, image
Tool / function useYes
API
API model IDgpt-5.5-pro
General
Knowledge cutoffDecember 1, 2025
Release dateApril 23, 2026
Benchmarks
Sourced evaluation scores, each verified against its primary source.
Humanity's Last Exam (with tools)
GPT-5.5 Pro: 0.572 (57.2%)