TL;DR: NotebookLM (now also called Gemini Notebook) answers only from the sources you upload, with citations back to your documents, and turns them into audio and video overviews – free for 100 notebooks with 50 sources each. Perplexity searches the live web for you, cites public sources, and lets you pick frontier models on its $20/month Pro plan. Pick NotebookLM to master a known set of documents; pick Perplexity to research questions you do not already have the material for.
NotebookLM vs Perplexity at a glance
| Feature | NotebookLM | Perplexity |
|---|---|---|
| Core idea | Chat with your own uploaded sources | AI search over the live web |
| Sources | PDFs, Docs, web pages and videos you add; answers grounded in them | Web results and premium sources, cited in the answer |
| Free tier | Free: 100 notebooks, 50 sources per notebook | Free: cited answers with limited Pro searches |
| Paid price | Via Google AI plans: Plus $4.99/month (100 sources/notebook), Pro $19.99/month (300 sources), Ultra from $99.99/month (500-600 sources) | Pro $20/month or $200/year; Max $200/month |
| Standout feature | Audio Overviews – podcast-style summaries of your sources – plus video overviews and slide decks | Deep Research reports, model picker and the Comet browser |
| Model choice | Google Gemini models only | Pro lets you select between leading models from several labs |
| Best for | Students, researchers and teams working from a fixed document set | Daily research, fact-checking and staying current |
Prices and limits checked October 2026 against Google help pages and Perplexity’s pricing page summaries.
How does NotebookLM work?
You create a notebook, add up to 50 sources on the free plan (each up to 500,000 words), and then ask questions. Because answers are grounded in those sources, NotebookLM cites the exact passage it used and rarely invents material from outside your set. The Studio tools are the differentiator: Audio Overviews turn a stack of papers into a listenable two-host summary, and newer video overviews and slide decks do the same visually. Paid headroom now comes bundled with Google AI subscriptions rather than a standalone NotebookLM plan, which is the main thing to understand before upgrading.
How does Perplexity work?
Perplexity starts from the opposite end: you ask a question, it searches the web, reads the results and writes a cited answer. The free plan is genuinely useful for quick checks. Pro at $20/month adds far higher usage, a picker of frontier models, larger file uploads, Deep Research runs that produce longer sourced reports, and access to premium sources. It is a research habit, not a document vault – it will not remember your private files as a persistent, queryable notebook the way NotebookLM organises them.
Which gives more trustworthy answers?
They earn trust differently. NotebookLM’s grounding means if the answer is in your documents, you can verify it in one click, and it will say so when your sources do not cover something. Its weakness is the mirror image: it knows nothing beyond what you fed it, and notebooks cannot be searched together. Perplexity’s answers are only as good as the live web it retrieves, which makes it far better for current events, prices and anything published after your documents were written – but you should still click through citations on anything that matters.
Which should you pick?
Pick NotebookLM if your work starts with documents: course readings, client files, research papers, manuals or interview transcripts. The free tier is generous enough that most people should start there.
Pick Perplexity if your work starts with questions: market checks, news, product research and quick cited briefings. Pro is the sensible paid step if you research daily.
Bottom line: Many researchers end up using both – Perplexity to find the material, NotebookLM to master it. If you can only pay for one, pay for the one that matches where your questions begin.
FAQ
Is NotebookLM free?
Yes. The free plan includes 100 notebooks with 50 sources each and standard Audio Overviews. Higher limits come with Google AI Plus, Pro and Ultra plans.
How much is Perplexity Pro?
$20/month, or $200/year. A Max plan at $200/month adds the highest limits and earliest features.
Can Perplexity answer questions about my own PDFs?
You can upload files to a thread or Space, but it is not a persistent notebook system like NotebookLM. For repeated work over the same document set, NotebookLM is the stronger fit.
Does NotebookLM search the web?
It can help you discover and import web sources into a notebook, but its answers stay grounded in the sources you add – it is not a general web answer engine like Perplexity.