Quick verdict
These two aren't really running in the same race. NotebookLM (85/100) answers from the documents you give it. Perplexity (83/100) answers from the live web and shows its sources. If your research starts with a pile of PDFs, back NotebookLM. If it starts with a question and an empty desk, back Perplexity. Using both is a sensible setup, not a cop-out.
Both scores are preliminary and reviewed from public docs. Heads up: Google renamed NotebookLM to "Gemini Notebook" in July 2026. Same product, new name. We've kept the NotebookLM name on this page.
The form lines
| NotebookLM | Perplexity | |
|---|---|---|
| AI Form Guide score | 85/100 | 83/100 |
| Works as claimed | 21/25 | 21/25 |
| Good for its stated job | 23/25 | 22/25 |
| Better than the default | 13/15 | 12/15 |
| Time to value | 8/10 | 9/10 |
| Price and value | 9/10 | 7/10 |
| Trust | 7/10 | 7/10 |
| Momentum | 4/5 | 5/5 |
| Answers from | Your sources | The web, with citations |
| Free to start | Yes, with a Google account | Yes, a free plan |
NotebookLM wins by two lengths, mostly on price and value and on how well it does its one job. Perplexity is quicker to get going and moves faster as a product.
What each one actually is
NotebookLM is Google's source-grounded notebook. You add your documents and ask questions against that set, and that constraint is the whole feature. According to Google's help pages, the free tier gives you 100 notebooks and up to 50 sources per notebook. Each uploaded source can run up to 500,000 words or 200MB. Usage runs on compute-based limits that refresh every five hours, up to a weekly limit. Paid Google AI plans lift those limits (Plus goes to 100 sources per notebook, Pro to 300). Google says the limits are subject to change, so check the product page before you rely on them.
Perplexity is an answer engine. You ask a question and it comes back with a cited answer from the web, and paid plans let you pick between models. When we checked on 19 Oct 2026, its pricing page listed a free plan, Pro at US$17/month billed annually and Max at US$167/month billed annually. Perplexity's help centre puts Max at US$200 month to month.