Perplexityvs.NotebookLM
Perplexity searches the web; NotebookLM answers only from sources you upload. Pricing, security evidence, published test results and which job fits which, side by side, plus the planned head-to-head test.
Perplexity AI
Vendor-described: Perplexity's help center lists the desktop and mobile browsers it supports.1
View product page →Vendor-described: Google's help page says it is available in browser to all users above the age of consent.2
View product page →Reviewed. Reviewed by our team from the vendor's pages and public sources, with an editor's rating. Not independently tested yet. No winner is declared and none of the content below is a finding.
Stage 2 of 5: Test conditions published
- 4
- Questions to answer
- 4
- Dimensions
- 9
- Documented differences
- 0
- Evidence records
What the documented evidence shows
Side by side, from vendor pages and published results. Not our tests.
Perplexity and NotebookLM (renamed Gemini Notebook by Google on 2026-07-16) are often compared because both give cited answers. They solve different problems. Perplexity searches the web for you. NotebookLM answers only from sources you give it. The right choice usually follows from where your evidence lives. Everything below is documented from vendor pages and published third-party results. We have not tested either tool.
Side by side
| Aspect | Perplexity | NotebookLM (Gemini Notebook) |
|---|---|---|
| Answers from | The web, files and connected apps | Only the sources you upload |
| Core job | Fast, cited answers to questions about the open web | Summaries, Q&A and study aids from a document set you chose |
| Free plan | Limited weekly usage | Standard: $0, 50 sources per notebook |
| Paid individual plan | Pro $17 a month billed annually; Max $167 a month billed annually | Google AI Plus $9.99 a month (100 sources); AI Pro $19.99 a month (300 sources) |
| Business plan | Enterprise Pro $34 per seat per month billed annually | Through Google Workspace or Gemini Notebook Enterprise on Google Cloud |
| Outputs beyond answers | Agent-style tasks (Perplexity Computer) and the Comet browser assistant | Audio and video overviews, slide decks, code execution on higher plans |
| Security evidence (vendor-listed) | SOC 2 Type II listed for Enterprise; other programs unconfirmed | Workspace edition: Google states no ISO, SOC or FedRAMP and no HIPAA BAA; Enterprise edition: per-program listings not checked |
| Training on your data | Perplexity says its agreements stop model providers training on its data | Workspace and personal data are not used for training, except feedback you submit (Google) |
| Editor's rating (not a test) | 5.6 out of 10 | 6.4 out of 10 |
Prices were read from each vendor's pricing page on 2026-10-24 and are annual-billing prices for Perplexity. Google One prices are monthly. See the Perplexity review and the NotebookLM review for dated sources.
Which one fits which job
| If you need to | Start with | Why |
|---|---|---|
| Check a current fact or survey a topic on the open web | Perplexity | It searches the web and cites what it found |
| Understand, summarize or quiz yourself on documents you already have | NotebookLM | It answers only from your sources, so every answer can be traced to them |
| Do literature work where every citation must hold | Neither alone | Both can mis-cite; open the sources, or use a tool built for academic literature |
| Buy for a team that needs SOC 2 coverage today | Perplexity Enterprise | SOC 2 Type II is listed for Enterprise; Google says the Workspace edition of NotebookLM has no SOC coverage yet |
| Keep costs near zero while you evaluate | Either free plan | Both have a free plan; NotebookLM's limit is sources per notebook, Perplexity's is weekly usage |
What independent tests have found
Two published results exist, and they measure different things, so they cannot be set against each other. We did not run either one.
- Perplexity: the Tow Center at Columbia Journalism Review tested eight AI search tools in February 2025 on news-excerpt attribution (1,600 queries). Perplexity answered 37 percent of queries incorrectly. This is a narrow task and is not a general accuracy measure.
- NotebookLM: a 2025 preprint (arXiv:2509.25498) tested ChatGPT, Gemini and NotebookLM on a reporting-style task over a 300-document corpus. 13 percent of NotebookLM outputs contained at least one hallucination, against 40 percent for ChatGPT and Gemini. The sample was small (40 annotated responses across tools), used one corpus, and is not peer reviewed.
The honest reading: citations make either tool easier to check, and neither removes the need to check. Grounding in your own documents appears to help, but one small preprint is not proof. Both numbers are listed with their limits in each review.
Security and data caveats
- For regulated or confidential work, the vendor's current terms for your exact plan decide, not this page.
- Google states that the Workspace edition does not support ISO, SOC or FedRAMP compliance and is outside the HIPAA BAA "at this stage". The Enterprise edition says it has many programs, but we did not verify the per-program pages.
- Perplexity's trust center lists SOC 2, ISO 27001:2022, a HIPAA gap assessment, PCI DSS SAQ A and FedRAMP 20x Low. Only SOC 2 Type II is tied to a plan (Enterprise Pro) on its pricing page.
What this page is not
It is not a test and it declares no winner. The planned head-to-head test further down fixes its conditions before any run, and results will be added only when they exist. Until then, the fastest way to decide is to run your own questions: use the steps in how to trial a research or writing tool.
Questions this comparison will answer
What we will examine, before any result exists.
This page lists what a fair comparison of Perplexity and NotebookLM needs to answer. It publishes questions first and conclusions only when evidence supports them.
- Source traceabilityWhat share of each tool's citations actually support the claim they are attached to?
- Accuracy of summariesDo summaries keep numbers, dates and qualifications intact?
- Handling of uncertaintyDoes each tool say so when the answer is not in the sources?
- Coverage and recencyHow do answers differ when the sources are the open web and when they are a supplied document set?
What each side says
Vendor claims, labeled as such, and what is still untested.
These are vendor-reported claims, not test results. We list them so you can see what each side says about itself, and we mark everything we have not tested.
| Dimension | Perplexity | NotebookLM | Evidence |
|---|---|---|---|
| Where it runs | Perplexity's help center lists the desktop and mobile browsers it supports.1 | Google's help page says it is available in browser to all users above the age of consent.2 | Vendor-reported |
| Data use | Perplexity's help center says it retains personal information while an account is active.3 | Google's help page says your content will not be used to directly train its foundational AI models.4 | Vendor-reported |
| Deployment | Not yet documented | Google's help page says work accounts access it as a Google Workspace core service or an add-on.4 | Vendor-reported |
| Usage limits | Perplexity's help center says free users get a limited number of Pro Searches per day.5 | Google's help page lists a limit of 500,000 words per source, or up to 200MB for local uploads.6 | Vendor-reported |
| Source traceability | Not yet documented | Not yet documented | Untested |
| Accuracy of summaries | Not yet documented | Not yet documented | Untested |
| Handling of uncertainty | Not yet documented | Not yet documented | Untested |
| Coverage and recency | Not yet documented | Not yet documented | Untested |
Vendor terms differ by plan and change over time. Check each vendor's current terms for the exact plan you would use.
Where this comparison stands
Test conditions, differences and the conclusion.
- PlannedSelected for evaluation
- Test conditions publishedTasks, versions, settings, runs, pass criteria
- Testing runBoth products tested under the published conditions
- Evidence recordedEach result linked to an evidence record
- ConclusionAdded only when evidence supports it
Test conditions
Test conditions are published before results: the tasks, tool versions, settings, number of runs and pass criteria are fixed in advance.
- Task set: 20 questions whose answers are verified in advance. Ten are answerable from a supplied set of ten documents, ten need current web sources, and five of the twenty are planted so that no source contains the answer.Published
- Method: for every answer, each cited source is opened and marked supported or unsupported. For NotebookLM the web pages are added as sources, so both tools see the same material.Published
- Measures: citation support rate (supported citations divided by all citations); key-fact retention (numbers, dates and qualifications kept divided by those in the reference); and the share of planted unanswerable questions where the tool says it cannot answer.Published
- Versions and plans: the plan, model and version of each tool are recorded for every run and published with the results.Published
- Repeats: every task is run at least three times per tool, alternating which tool goes first, and every run is reported, failures included.Published
- Fixed in advance: prompts, inputs, reference answers and scoring rubrics are written and published before any run, and the operator pastes prompts verbatim.Published
- Publication rule: nothing is published as a result until every planned run is recorded, and each figure is shown with its sample size.Published
Documented differences
Differences are listed here only when each is supported by a linked evidence record.
Conclusion
A conclusion is added only when the evidence supports it. Until then, this page makes no claim about which option is better.
Limitations
- No testing has been run, so there are no results.
- Test conditions are fixed before any run and may be extended, never changed after results exist.
- No winner is declared.
The planned test, in full
Conditions, criteria and result cells, fixed before any run. Every result says Not yet run.
Short answer: Perplexity searches the web for cited answers; NotebookLM answers only from documents you upload. Choose Perplexity for current web questions and NotebookLM for your own document set. Both can mis-cite, so open the sources. No head-to-head test has been run, so no winner is declared.
What are the test conditions?
- Task set: 20 questions whose answers are verified in advance. Ten are answerable from a supplied set of ten documents, ten need current web sources, and five of the twenty are planted so that no source contains the answer.
- Method: for every answer, each cited source is opened and marked supported or unsupported. For NotebookLM the web pages are added as sources, so both tools see the same material.
- Measures: citation support rate (supported citations divided by all citations); key-fact retention (numbers, dates and qualifications kept divided by those in the reference); and the share of planted unanswerable questions where the tool says it cannot answer.
- Versions and plans: the plan, model and version of each tool are recorded for every run and published with the results.
- Repeats: every task is run at least three times per tool, alternating which tool goes first, and every run is reported, failures included.
- Fixed in advance: prompts, inputs, reference answers and scoring rubrics are written and published before any run, and the operator pastes prompts verbatim.
- Publication rule: nothing is published as a result until every planned run is recorded, and each figure is shown with its sample size.
What will we measure for Perplexity and NotebookLM?
| Question | Perplexity | NotebookLM |
|---|---|---|
| What share of each tool's citations actually support the claim they are attached to? | Not yet run | Not yet run |
| Do summaries keep numbers, dates and qualifications intact? | Not yet run | Not yet run |
| Does each tool say so when the answer is not in the sources? | Not yet run | Not yet run |
| How do answers differ when the sources are the open web and when they are a supplied document set? | Not yet run | Not yet run |
How do we keep the comparison fair?
Every figure above stays empty until the runs exist. Prompts, inputs, answers and rubrics are fixed first, each task is repeated, failures are published, and judgment calls are labelled as editorial next to the measured numbers. If a condition has to change after results exist, the old results are kept and the change is logged on the updates page.
Read each review first: Perplexity and NotebookLM. See how to read an evaluation and the methodology.
The exact prompts, rubrics and datasets are in the full test protocols.
How do I compare them myself?
A method you can run on your own work today.
Ask questions whose answers you already know, then open every cited source and confirm it supports the claim. Check that summaries keep numbers, dates and qualifications, note what the tool can search and how recent that is, and see whether it flags conflicting or missing sources.
- Ask questions whose answers you can already verify.
- Open each cited source and confirm it supports the claim.
- Check that summaries keep numbers, dates, and qualifications intact.
- Note what the tool can search and how recent its sources are.
- See whether it says so when sources conflict or are missing.
Related reading
Frequently asked questions
Short answers to common questions.
Which is better for research, Perplexity or NotebookLM?
We have not tested either, so we do not declare one better. They work differently: Perplexity searches the web, while NotebookLM works from sources you supply. The planned test measures citation support, summary accuracy and handling of missing answers on both.
Why are there no results yet?
The test conditions are published first so the method can be checked before any outcome is known. Nothing has been run, so no figures or winner are published.
Can I run this comparison myself?
Yes. Use the same inputs for both tools, write your scoring rubric before you start, repeat each task at least three times, and keep failed runs in the results. Our guides describe how to read an evaluation and what to record.
Sources and further reading
Vendor pages behind the claims above.
- Perplexity AI: perplexity.aiVendor page, captured October 21, 2026.
- Google: support.google.comVendor page, captured October 10, 2026.
- Perplexity AI: perplexity.aiVendor page, captured October 21, 2026.
- Google: support.google.comVendor page, captured October 10, 2026.
- Perplexity AI: perplexity.aiVendor page, captured October 21, 2026.
- Google: support.google.comVendor page, captured October 10, 2026.
Editorial independence. Commercial relationships, affiliate links and sponsored placements are disclosed and never determine evaluation scores. See the affiliate disclosure and the editorial policy.