Gemini Notebook (formerly NotebookLM): Source Limits and Overviews

Gemini Notebook's model uses the sources you upload to answer your questions or complete your requests. HTML web sources contribute only scraped text; images, embedded videos, nested webpages, and paywalled webpages are not imported.

File Size and Count Limits

Each source can contain up to 500,000 words or up to 200MB for uploaded files. Free users can include up to 50 sources in a notebook.

You can generate Audio Overviews in 80+ languages.

Audio and Video Overview Specifications

In the Brief format of an Audio Overview, a single speaker delivers the key takeaways of a document in under two minutes. The Short format of a Video Overview covers the key concepts of your sources in videos of about 60 seconds.

Output Reliability and Stability Limits

When you update or delete a source, studio outputs generated with that source do not change. Audio Overviews, including voices, are AI-generated and may contain inaccuracies or audio glitches. Video overviews, including voices and visuals, are AI-generated and may contain inaccuracies or audio glitches.

Consider generation time when choosing between formats: Gemini Notebook may take a couple of minutes to generate an Audio Overview, and a Video Overview sometimes takes more than 30 minutes.

The observation window is 2026-10-06 through 2026-11-05. Last30Days discovered 7 items; 4 were retained after requiring a direct mention of the topic, an HTTPS URL, a substantive excerpt, and deduplication. Included/discovered counts by source are reddit: 1/1, youtube: 1/1, web: 2/5. Engagement was known for 1/4 retained items; no engagement was inferred for the remainder. This section reports public posts and videos observed in the window, not vendor policy or a market-wide statistic. The sample is not representative of the whole market, and each observation links to its source below.

• 2026-10-23 · reddit: overview of SurfSense I am one of the maintainers of SurfSense, so this is self promotion. I am posting because I would like feedback on the design from people who build with LLMs. SurfSense is an open-source (Apache-2.0) desktop app for Windows, macOS and Linux: cited Q&A over your documents, plus an agent that writes and edits Word, PDF, PowerPoint and… (source)
• 2026-11-04 · youtube: Want to study smarter, save time, and get more from your university notes? Discover how to use NotebookLM with 18 proven AI study workflows designed for university students. In this course, NotebookLM Mastery for University Students: 18 Proven AI Study Workflows, you'll explore practical ways to use Google's AI-powered research and learning assistant to o… (source)
• 2026-10-22 · web: NotebookLM turns your own sources into a searchable research workspace. Add PDFs, Google Docs, Google Slides, websites, or public YouTube URLs, ... (source)
• 2026-10-22 · web: Select “Video Overview”: Click the Video Overview option. NotebookLM will analyze your sources and generate the video. This may take a few minutes ... (source)