Copilot Notebook reference size limit

Question

What is the current size limit of a reference added to a Notebook in copilot

Answer 1

For Copilot Notebooks, the documented limits apply to the number and type of references, not to a specific per-file size cap unique to Notebooks:

• Up to the first 100 references in a notebook are used for grounding; additional references beyond the first 100 are ignored for grounding.
• Supported reference file types are: .docx, .pptx, .xlsx, .pdf, .loop, .page, and OneNote pages.

For file size and length, Copilot behavior follows the general document-length guidance used across Microsoft 365 Copilot rather than a Notebook-specific size limit. Relevant guidance includes:

• When summarizing or referencing content, Copilot works effectively up to about 1.5 million words or 300 pages.
• For Q&A over a document, results work best if the document is under ~7,500 words.
• For rewrite scenarios, documents work best if under ~3,000 words.

In extensibility scenarios where SharePoint files are referenced (for example via agents), additional practical limits apply:

• For SharePoint files referenced by URL, keep files to a maximum of 36,000 characters (~15–20 pages) to help Copilot reliably retrieve the right content.
• For embedded file content, Copilot indexes the first 750–1,000 pages (~1.8 million characters) of each embedded file.

These limits describe how much of a referenced file Copilot can effectively read and use, rather than a hard “upload size” limit specific to Notebook references.

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References:

• Get answers and insights about your Microsoft 365 Copilot Notebook
• How Microsoft 365 Copilot Notebooks works
• Keep it short and sweet: a guide on the length of documents that you provide to Copilot
• Optimize content retrieval