AI Glossary Term
What does “Context Window” mean?
The maximum amount of input tokens a language model can process at once.
How Context Window works
Example
If you paste a 300-page report into a chatbot whose window is smaller than the report, the model cannot read all of it at once. Older parts may be cut off or summarized, and it can lose track of details that fell outside the window.
Why it matters
The context window limits how much a model can consider at one time, which affects long documents and long chats. Larger windows help, but quality can still drop on very long inputs.
Common questions
Is a context window measured in words?
No, in tokens. A token is often a short word piece, so a window of 100,000 tokens holds roughly 75,000 English words.
Does the model remember things outside the window?
Not on its own. Anything outside is invisible unless it is brought back in, for example through retrieval or a saved summary.
Is a bigger window always better?
Not always. Longer inputs cost more and models can miss details buried in the middle of very long text.