Skip to main contentContext window explained — How much context fits at once
The amount of information a model can handle in one processing context, usually measured in tokens. Think of a work surface with limited space.
An everyday example
A long contract, conversation history and your instructions can all occupy that space.
When you’ll encounter it
Check it before working with large files or long conversations. How input and output share the limit depends on the model.
What to watch for
A larger window does not guarantee accurate recall of every detail or permanent memory. Applications may summarize or remove earlier messages.
Related terms & sources
Prepared from the public sources below. Examples illustrate the concept. Reviewed on 2026-10-15.