NotebookLM is Google’s tool for chatting with your own stuff. You upload PDFs, notes or links, and it answers questions using only what you gave it. (Google renamed it Gemini Notebook in July. Same product, new sign on the door.) The confusing part isn’t the price. It’s that you don’t really buy NotebookLM at all. You buy a Google AI plan, and NotebookLM comes along with it.
Everything below is accurate as of this morning, and AI pricing changes constantly. The specific numbers will drift. The way to think about the decision holds up longer.
What the money buys
Free: 100 notebooks, up to 50 sources in each.
Google AI Plus ($4.99 a month): 200 notebooks, 100 sources each, and about double the free usage.
Google AI Pro ($19.99 a month): 500 notebooks, 300 sources each, about four times the free usage, and a small number of the fancier Cinematic Video Overviews.
Google AI Ultra ($99.99 a month and up): 500 or more sources per notebook and the highest limits.
Every plan caps a single source at 500,000 words, which is a lot of words. The paid plans also bundle other Gemini features and Google storage, so NotebookLM is rarely the only thing you’re paying for.
What it doesn’t buy
A clear number, mostly. Google used to publish daily caps (the free plan got 50 chats and 3 Audio Overviews a day). On September 2, it switched to a usage budget that refills every five hours, up to a weekly limit. Long chats and video overviews eat more of it than quick questions do. So “four times the usage” tells you how the plans compare, not how many podcast-style overviews you’ll actually get.
If you want hard numbers, the work version still has them. Google Workspace Business Standard ($14 a person) lists 500 chats and 20 Audio Overviews a day.
The math
Most people never need to pay. Fifty sources in one notebook is a pretty big research project, and 100 notebooks is a lot of projects.
Plus at $4.99 is mainly about room: double the sources per notebook and double the usage. Pro is the one to look at if you already want Gemini’s paid features, since you’re getting both for one price.
The test that outlasts the prices: have you ever seen a “you’ve hit your limit” message? If not, free is doing its job. If you see it every week, the next tier up is probably worth the coffee money.