[ GLOSSARY ]
What is a context window?
Definition
AI conceptsContext window
A context window is the amount of text, measured in tokens, that an AI model can consider at once, including the conversation so far and any pasted documents.
Why it matters for schools
Window size differs by plan. Free ChatGPT's context is 27K tokens, about 12 pages; the Plus plan's reasoning context is 256K. A long reading or a big assignment may not fit in a small window, and every turn resends the whole conversation, so long chats cost more. When text does not fit, a tool may refuse it or lose earlier parts of the conversation, so ask students to paste the section they are working on rather than a whole book.
[ FAQ ]
Questions and answers
What is a context window in AI?
The amount of text a model can consider at once, counted in tokens.
How much text fits in free ChatGPT?
Its context is 27K tokens, about 12 pages (OpenAI, read Oct 18, 2026).
Why do long chats cost more?
Each turn resends the conversation so far, so input grows with every message.
[ SOURCES ]
Sources
Facts checked Oct 18, 2026.
- 1OpenAI, ChatGPT pricing and GPT-6 models help articleRead Oct 18, 2026 · chatgpt.com
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