The NotebookLM source limit is 50 sources per notebook on the free plan, and paid Google AI plans raise it to 100 on Plus, 300 on Pro and 500 or 600 on Ultra, according to Google’s Gemini Notebook plans page.
As of November 10, 2026, NotebookLM is called Gemini Notebook, and Google says these limits are subject to change. The Ultra 20 TB plan allows 500 sources per notebook and the Ultra 30 TB plan allows 600. Notes have a separate cap of 500 per notebook, or 600 on Ultra. You can create 100 notebooks free, 200 on Plus and 500 on Pro or Ultra. Sharing a notebook does not raise the source limit for any collaborator.
Each source can hold up to 500,000 words, and uploaded files can be up to 200 MB, per Google’s guide to adding sources. Google Slides sources are limited to 100 slides and Google Sheets to 100,000 tokens. YouTube videos have no length limit unless the captions pass 500,000 words.
Related: How much does NotebookLM cost?, What is the Gemini file upload limit? and What is the Gemini context window?
Source: Google, “Learn about Gemini Notebook’s plans” (Gemini Notebook Help) and Google, “Add or discover new sources for your notebook” (Gemini Notebook Help)
Image: Gemini Notebook logo by Google, public domain (trademarked), via Wikimedia Commons. Placed on a white background and resized. Gemini Notebook, NotebookLM and Google are trademarks of Google LLC. FreeAnswers is not affiliated with or endorsed by Google.