Keep it short and sweet: a guide on the length of documents that you provide to Copilot
Applies To
Word for Microsoft 365 PowerPoint for Microsoft 365 Word for Microsoft 365 for Mac PowerPoint for Microsoft 365 for Mac Word for the web PowerPoint for the web Word Web AppNote: This article was partially created with the help of AI. An author reviewed and revised the content as needed. Read more about Microsoft and Responsible AI practices.
When you write Copilot prompts, you can provide Copilot with information or samples - the source for Copilot to use. For example, you can ask Copilot in Word: Write a marketing plan outline based on the product features described in this document. But to get the best output from Copilot, it’s important to consider the length of the content you provide to Copilot, as there are limits to the size of documents that Copilot can read at once.
Depending on the type of tasks you give Copilot, there are times that Copilot will focus only on the beginning of the document (up to its limits) and then ignore anything beyond that. For example, when you ask a question about a specific topic in a long document, document length typically will not impact the ability to get a result based on how the Large Language Models (LLMs) reason over the content. But if you ask for a summary of a long document, the task requires the entire document context to inform the output. For the latter case, length limits do come into play and impact output.
For scenarios where the entire document context is needed for Copilot to provide answer, a couple of good rules of thumb on the length of the document you provide to Copilot:
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When summarizing content or referencing content while using Copilot to create a draft, keeping the total of all of your referenced content to around 80,000 words or less helps Copilot work effectively.
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Asking Copilot questions about the document works best if the document is less than about 7,500 words.
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Rewrite works best on a document that is less than about 3,000 words.
Notes:
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Different languages will have slight variations in these limits, so you may need to adjust the page or word limits based on the language you use.
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Large language models (LLMs) tend to prioritize content that is at the beginning and end of a file. Accordingly, the results you get may give less attention to content that was in the middle of a long file.
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While these page/word limits are currently a good guideline, we are constantly working to expand Copilot's capabilities, and these limits will increase over time. When they do, this page will be updated to reflect any changes.
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While we are working on functionality that allows you to point Copilot to a specific section or page range in a document, that experience does not exist today.
Keeping files you provide to Copilot within these size limits helps Copilot read and respond to your documents accurately and effectively. If your document is longer than these limits, Copilot might still be able to help, but it'll focus only on the first part of your document. It would be like reading only the first few chapters of a book and trying to guess the rest (which is what Copilot ends up doing in this case).
Tips for Longer Documents
Here are some ways that you can use longer documents with Copilot:
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Break It Down: If you have a long document, consider splitting it into smaller documents and providing them to Copilot separately. This way, Copilot can handle each part effectively.
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Summarize in Parts: For long reports or manuscripts, you can try summarizing them in chunks with Copilot. Today you can do that by copying/pasting chunks into separate documents and summarizing sections separately. This helps Copilot to give you more precise and relevant responses.
When using Copilot, think of it as having a conversation with your friend. You wouldn't discuss a whole encyclopedia at once, right? Similarly, keep your document references concise and to the point for the best experience with Copilot.
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