Take notes on YouTube, beside the video
The LunaNotes extension docks a sidebar next to the YouTube player: timestamped notes, the transcript, AI tools and questions about what you are watching. Everything you keep lands in your library.
Free to start · used by 44K+ note-takers
This page covers the YouTube side of the extension. It also saves any other page you are on as a bookmark. See the full extension page →
The Calvin cycle
17:40 Runs in the stroma, no light needed directly.
18:05 RuBisCO fixes CO₂ onto RuBP (5 carbons).
- Splits into two 3-carbon molecules
- Spends the ATP + NADPH from stage one
19:10 RuBisCO is slow, so plants make a lot of it
Five tabs, one video
On a watch page the sidebar opens on this video and keeps each job in its own tab. Every tab has a shortcut, so your hands can stay on the keyboard.
Notes pinned to the second you wrote them
Every note you take on this video, each with the time it was started at. Click the time to seek; open the note to keep writing.
- Alt N starts a new note at the current time
- Insert the time or a frame screenshot mid-note
- Pick the workspace, tags or a template as you write
Open this tab with AltShiftN
Notes
Search ⌘KPhotosynthesis · Lecture 4
3 notes
Light-dependent reactions
Thylakoid membranes. Water is split, O₂ released, energy stored as ATP + NADPH.
The Calvin cycle
Stroma, no light needed directly. RuBisCO fixes CO₂ onto RuBP.
C4 vs CAM
Both avoid photorespiration: C4 splits it in space, CAM in time.
The captions, as lines you can read
The video's captions as clean lines that scroll with playback. Search for the term you half-remember, click the line, and the video seeks there.
- Copy the whole transcript in one click
- Translate it line by line, under the original
- Turn off auto-scroll to read at your own pace
Open this tab with AltShiftT
Transcript
Search ⌘KSo the light reactions leave us with two things: ATP and NADPH.
Neither of them is sugar yet. That's what the second stage is for.
The Calvin cycle runs in the stroma, and it doesn't need light directly.
Its key enzyme, RuBisCO, grabs CO₂ from the air and attaches it to a five-carbon sugar.
The result splits into two three-carbon molecules, and that's where glucose starts.
RuBisCO is slow, which is why plants make so much of it.
Questions about the video you are watching
The same Assistant as in the LunaNotes app, already holding this video. It opens with starter questions, and every conversation is in your app history later.
- Summarize, explain simply, or make flashcards
- Follow up as you would in any chat
Open this tab with AltShiftA
One click for the usual jobs
Summary, Chapters, Fact Check and What viewers say each save a note to your library. Subtitles downloads the captions. Flashcards and Diagram make a deck or a map of the video.
- A result someone already generated costs nothing
- Practice exam tests you on the video
Open this tab with AltShiftV
Flashcards that are due, without leaving YouTube
Up to ten due cards in a session, graded the same way as in the app, so a few minutes between videos count towards your review.
- Make flashcards of this video from here
- Cards come back the day you're about to forget them
Open this tab with AltShiftR
What you get before and after signing in
Install and try the tools straight away. An account is what keeps things: notes, transcripts and chats need one, and the free one is enough for most of it.
Credits are spent only when AI makes something new. A summary someone already generated for this video is free to open. See the plans
| On YouTube | Signed out | Free account | Starter or Plus |
|---|---|---|---|
| Summary, Chapters, Fact Check | 3 runs per install, free | A new result uses credits; one already made is free | The same, from a bigger allowance |
| Timestamped notes and the marker strip | Not available | Free, no note limit | Free, no note limit |
| Transcript: read, search, copy | Not available | Free | Free |
| Subtitles as an .srt file | Not available | Free | Free |
| Translate the transcript | Not available | Credits for a new translation | Credits for a new translation |
| What viewers say | Not available | Credits for a new summary | Credits for a new summary |
| Ask about the video | Not available | Credits per message | Credits per message |
| Flashcards and diagrams of the video | Not available | Credits; up to 5 decks and 5 diagrams | Starter 20 of each; Plus unlimited |
| Practice exam | Not available | 2 a month | Starter 10 a month; Plus unlimited |
| Review due flashcards | Not available | Free | Free |
| Videos without captions | Not available | Not available | Plus transcribes them, up to 20 minutes |
| AI credits a month | Not available | 1,000 | Starter 30,000; Plus 120,000 |
Installs from the Chrome Web Store, into any Chromium browser
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Edge
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Opera
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Vivaldi
Firefox and Safari are not supported.
It watches YouTube with you, not your browsing
The sidebar needs the YouTube page to sit beside the player. It does not need anything else, and it does not ask for it.
The permissions, one by one, are on the extension page.
- 01
It runs on YouTube, and only there, by itself
The sidebar is the extension's one content script, and it is limited to youtube.com. It docks beside watch pages and Shorts, and nowhere else.
- 02
Anywhere else, it waits to be asked
On other sites it acts only when you use it, from the toolbar icon, the right-click menu or the side panel, and then only on that tab. It has no standing access to the pages you browse.
- 03
An account is only for keeping things
The 3 free tool runs need no sign-in. Notes, the transcript and the Assistant do, because what you make goes into a library that is yours.
Questions about YouTube extension
What people ask before they try it.
Install it from the Chrome Web Store, then open any YouTube video. A LunaNotes tab appears at the side of the page; click it, the toolbar icon, or press Alt L to open the sidebar. You can also set it to open by itself in settings.
Not to try it. Signed out, you can run Summary, Chapters or Fact Check on a video 3 times. Notes, the transcript, the Assistant and the other tools need a free account, so what you make has a library to live in.
The extension is free, and so are notes, timestamps, the transcript and Subtitles. With an account, a new Summary, Chapters, Fact Check or What viewers say result, a new translation and messages to the Assistant use your LunaNotes credits; a result someone already generated is free. The free plan includes 1,000 credits a month.
Yes. Notes, timestamps, tool results, flashcards and chats are saved to your LunaNotes account as you go, so they are in the app and on any device.
Yes. The sidebar opens on Shorts as well as regular watch pages.
Drag the sidebar wider or narrower, close it with Esc, or hide its side tab in settings. Every keyboard shortcut can be turned off there too.
The sidebar does. On every other site, the toolbar icon saves the page you are on as a bookmark in your library instead. The full extension page covers that side.
Works even better with
YouTube extension is one part of LunaNotes. These pick up where it leaves off.
Explore what else LunaNotes does
Each one works on the same notes, so what you make in one feeds the rest.
Make it studyable
Bring it in
- Video workspace Your video library, with notes attached
- Timestamped notes Notes that jump back to the moment
- YouTube courses Work through a playlist in order
- Bookmarks Save any page, find it again
- Meeting notes An AI notetaker for Google Meet
- Podcasts Subscribe, listen, keep the notes
- Files PDFs, documents and images you upload