Context Window
1 min read · Reviewed 17 Oct 2026
In short
How much information an AI can consider at one time.
In plain English
When you chat with an AI, it can only "see" a certain amount of text at once — your messages, its replies, and any documents you've added. That limit is the context window. Go past it and the model starts losing track of what was said earlier in the conversation.
A real example
Paste a 100-page report into a chatbot and ask about page 2, and it may answer well. Keep chatting for a long time, though, and it can "forget" that report — because the older text has scrolled out of its context window.
Why it matters
Knowing about the context window helps you get better results: keep long tasks focused, re-paste key details when a chat gets long, and pick a tool with a larger window when you're working with big documents.
