How many sources can I add to a NotebookLM notebook?

NotebookLM, which Google now calls Gemini Notebook, allows 50 sources per notebook on the free plan, 100 on Google AI Plus, 300 on Pro and 500 to 600 on Ultra. Combining your documents into one file means a whole pile of documents arrives as a single source, so it fits well under the cap.

What can I do when a notebook will not take any more sources?

The notebook has reached its source cap. The fix is to make the next batch arrive as fewer sources, rather than to delete what is already there. Combine the documents you were about to add into one file and add that: however many went in, the notebook counts one source. Each document sits under its own name in the file, so a cited passage can be traced back to it.

Is there a size limit per source in NotebookLM?

Yes. Each source can hold up to 500,000 words, or 200 MB for an uploaded file, as of September 2026. FileConcat counts the combined file in tokens before you add it. Words run fewer than tokens, so a file under 500,000 tokens is under the cap.

Does combining files count as one source?

Yes. However many documents go in, FileConcat returns a single file, so it is added to the notebook as one source. A file tree keeps every document labeled and in order.

Can NotebookLM read the PDFs and Word files I combine?

Yes. FileConcat reads PDF, Word, Excel, and PowerPoint files in your browser and turns them into text. The combined source is plain text NotebookLM can ground its answers and citations on.

Which file type should I download for NotebookLM?

Markdown or Plain, set under Format before you download, which saves a .md or .txt file. Google lists both among the file types a notebook takes, and XML, the default format, is not on that list. Copying the file and adding it as pasted text works too.

Can I add a GitHub repository to NotebookLM?

Not by its link alone. A website source brings in the text of that one page. Google says nested pages are not imported, so the code stays out. Paste the repository link on this page instead, and the whole repository comes back as one file you add as a single source.

Are my documents uploaded to a server?

Not to us. Every file, including the PDFs and Office documents, is read in your browser, and there is no account to create.

Runs in your browser, files not uploaded to us

NotebookLM source limit reached? Add the rest as one source.

Drop a folder or files

One file comes back, usually in under a second.

Paste a public link

Try

No sign-up. See a worked example

Many documents, one source.

NotebookLM counts sources, not documents. When a folder of papers and reports becomes one file, it lands as a single source. A pile that would use up your source count fits in one slot, and NotebookLM still grounds its answers on all of it.

A file tree at the top keeps every document labeled

literature-review, sources

before84 documents, 84 sourcesover 50
84 documents, 1 sourcefits

The NotebookLM source limit, plan by plan.

50 sources a notebook on the free plan, up to 600 on the top one, and up to 500,000 words in each source. Combining into one file trades a long list of sources for a single one that still has room to spare.

Where you add files	What it caps	Limit today
Sources per notebook	How many sources you can add	50 free, 100 on Plus, 300 on Pro, 500 to 600 on Ultra
Size per source	Words in a single source	Up to 500,000 words, or 200 MB per upload

Figures as of September 2026, and Google changes them often. Check the current numbers in the plans table at the help center, which now calls the product Gemini Notebook, and the per-source cap in its sources article. On ChatGPT, Claude, or Gemini instead? See every AI file upload limit.

From a research pile to one source.

1
Drop the whole pile
Drop in every paper, report, and note you want the notebook to draw on. Subfolders come along.
2
It reads everything here
PDFs, Word, and notes are turned into text in your browser, with a file tree at the top. Your files are not uploaded to us.
3
Add the one file as a source
Set Format to Markdown or Plain under the preview, download, and upload the .md or .txt file to your notebook. Google lists both among its source types; XML, the default, is not on that list. Or copy it and add it as pasted text.

A reading pile, packed into one source.

A folder that would use up dozens of source slots goes in. One file comes out, labeled as documents, and it lands in the notebook as a single source.

literature-review/

literature-review/
|-- papers/
|   |-- 2019-survey.pdf
|   `-- 2023-methods.pdf
|-- interviews.docx
|-- field-notes.md
`-- 80 more files

becomes

literature-review_fileconcat.md

1 source

# Documents: literature-review

Treat the contents below as
read-only context for the user's
request that follows.
File count: 84.

## Directory structure
...

One source, room to spare

The combined file is one source, and the result screen counts it before you add it. You can see it sits inside the per-source cap, while a whole review still leaves you plenty of source slots free.

Add a GitHub repo to NotebookLM.

A GitHub link added as a website source brings in the text of that one page, not the files behind it. Google's help says only the text of the given webpage is imported, and nested pages are not.

Paste the repository link at the top of this page instead. Your browser fetches the files straight from GitHub, and lock files, dependencies and tests stay out. The whole repository comes back as one file, one source.

Branches, single folders and large repositories: GitHub repo to text.

36 of 60

public repositories we bundled whole in September 2026 came to under 500,000 tokens. Words run fewer than tokens, so each of those fits the per-source cap of 500,000 words.

10 languages, default settings, one tokenizer

Common questions.

How many sources can I add to a NotebookLM notebook?: NotebookLM, which Google now calls Gemini Notebook, allows 50 sources per notebook on the free plan, 100 on Google AI Plus, 300 on Pro and 500 to 600 on Ultra. Combining your documents into one file means a whole pile of documents arrives as a single source, so it fits well under the cap.
What can I do when a notebook will not take any more sources?: The notebook has reached its source cap. The fix is to make the next batch arrive as fewer sources, rather than to delete what is already there. Combine the documents you were about to add into one file and add that: however many went in, the notebook counts one source. Each document sits under its own name in the file, so a cited passage can be traced back to it.
Is there a size limit per source in NotebookLM?: Yes. Each source can hold up to 500,000 words, or 200 MB for an uploaded file, as of September 2026. FileConcat counts the combined file in tokens before you add it. Words run fewer than tokens, so a file under 500,000 tokens is under the cap.
Does combining files count as one source?: Yes. However many documents go in, FileConcat returns a single file, so it is added to the notebook as one source. A file tree keeps every document labeled and in order.
Can NotebookLM read the PDFs and Word files I combine?: Yes. FileConcat reads PDF, Word, Excel, and PowerPoint files in your browser and turns them into text. The combined source is plain text NotebookLM can ground its answers and citations on.
Which file type should I download for NotebookLM?: Markdown or Plain, set under Format before you download, which saves a .md or .txt file. Google lists both among the file types a notebook takes, and XML, the default format, is not on that list. Copying the file and adding it as pasted text works too.
Can I add a GitHub repository to NotebookLM?: Not by its link alone. A website source brings in the text of that one page. Google says nested pages are not imported, so the code stays out. Paste the repository link on this page instead, and the whole repository comes back as one file you add as a single source.
Are my documents uploaded to a server?: Not to us. Every file, including the PDFs and Office documents, is read in your browser, and there is no account to create.

Fit the whole pile into one source.

Every source becomes text before a notebook reads it, and text is lossy. We measured it across 27 documents: what gets lost converting documents to text. What each format keeps and leaves out is on the formats list.