# Context window

> The maximum amount of text, counted in tokens, that a model can take in and produce in a single request.

Source: Promptea — https://www.promptea.me/en/glossary/context-window · Language: English · Last updated: 2026-11-09

## What it means

- Definition: the context window is the model's working memory for one request. Your instructions, pasted documents, the conversation so far and the answer all have to fit inside it. It is measured in tokens, roughly three quarters of an English word each.
- Why it matters: past the limit, older content is dropped or the call fails. Even inside the limit, a model can pay less attention to material buried in the middle of a very long context.
- How to apply it: paste only the relevant excerpt, put the instruction and the key facts where they are easy to find, summarize earlier conversation, and start a fresh chat for a new task.
- Window sizes differ by model and change over time. Promptea's models pages list each current model's context window with the date it was verified against the provider's documentation.

## Example

```text
I have a long document. Below is only the section relevant to this task.

Section:
"""[paste the excerpt, not the whole document]"""

Task: [what to do with this section]
If you need another part of the document, tell me which one instead of guessing.
```

[Open in Promptea](https://www.promptea.me/en/analyzer?prompt=I+have+a+long+document.+Below+is+only+the+section+relevant+to+this+task.%0A%0ASection%3A%0A%22%22%22%5Bpaste+the+excerpt%2C+not+the+whole+document%5D%22%22%22%0A%0ATask%3A+%5Bwhat+to+do+with+this+section%5D%0AIf+you+need+another+part+of+the+document%2C+tell+me+which+one+instead+of+guessing.&purpose=summarization&target=claude)

## Frequently asked questions

### What happens when I hit the context limit?

The model either truncates earlier content or returns an error, depending on the product. Stay well under the limit by being selective about what you include.

### Is a bigger context window always better?

No. It lets you include more, but more text can dilute attention and raises cost and latency. Include what the task needs, not everything you have.

## Related

- [Context engineering: how to structure what you give an AI for better outputs](https://www.promptea.me/en/guides/context-engineering)
- [Summarization prompts that preserve meaning (not just reduce length)](https://www.promptea.me/en/guides/summarization-prompts)
- [Prompt chaining: how to break complex tasks into sequential AI steps](https://www.promptea.me/en/guides/prompt-chaining)
- [Tokens](https://www.promptea.me/en/glossary/tokens)
- [Context engineering](https://www.promptea.me/en/glossary/context-engineering)