Model page
GPT-3.5 Turbo
Legacy GPT model for cheaper chat and non-chat tasks.
Key dates
We use concrete dates and keep them consistent across the site.
Capability
Intelligence
Low
Capability
Speed
Slow
Capability
Context window
16,385 tokens
Capability
Max output
4,096 tokens
Capability
Knowledge cutoff
September 1, 2021
API
Supported endpoints
v1/chat/completions · v1/responses · v1/assistants · v1/batch · v1/fine-tuning
Modalities
Input and output
Input: Text
Output: Text
Features
Availability notes
Fine-tuning supported
ChatGPT
GPT‑4o retirement (ChatGPT)
OpenAI is retiring GPT‑4o inside ChatGPT on February 13, 2026. This does not automatically imply API removal.