GPT-5.5

Published

Apr 23, 2026

GPT-5.5 is an AI model developed by OpenAI (United States), first published in April 2026. It works in the multimodal, language and vision domain, on tasks such as language modeling/generation and question answering.

Epoch AI has no training-compute estimate for this model. Training ran on NVIDIA GB200,NVIDIA GB300 (Blackwell Ultra).

Access: API access. Its weights are not openly released. Epoch AI rates the confidence of this record as likely.

Full record

Organization: OpenAI
Country of organization: United States
Domain: Multimodal, Language, Vision
Task: Language modeling/generation, Question answering
Training hardware: NVIDIA GB200, NVIDIA GB300 (Blackwell Ultra)
Model accessibility: API access
Open weights: No
Epoch confidence: Likely

Benchmark results

01

Epoch Capabilities Index

ECI Score

158.5