GPT-5.5
GPT-5.5 is a model you reach through an API — too large to self-host, so this page covers what it does, how to access it, and what to run locally instead.
PARAMETERS
n/a
FORMAT
API
RUNS LOCALLY
No
BEST FOR
Quality, Reasoning, Multimodal
You don't run GPT-5.5 locally
Access is through the hosted API.
Apr 23, 2026 OpenAI flagship. Pro and Instant variants follow May 5. Cloud only. Parameter count undisclosed (cloud API).
Strong local alternatives
More OpenAI models
Frequently asked questions
Can I run GPT-5.5 locally?
Not realistically. GPT-5.5 is a vendor-undisclosed-size model; a Q4-class build would need far beyond any consumer machine. The hosted API or a smaller open model is the practical path.
How do I access GPT-5.5?
Through the vendor-hosted API. See the official source linked on this page.
What is the best local alternative to GPT-5.5?
Qwen3 235B A22B is the strongest local model we track (235B). It runs on a single high-memory Mac or GPU; see its page for exact hardware.
Cite this page
ModelFit: GPT-5.5 — specs, memory math and hardware verdicts. https://modelfit.io/models/gpt-5.5/ (dataset updated 2026-09-03, CC BY 4.0).