# Merge NotebookLM notebooks into one or compare two > Merge NotebookLM notebooks into one. Kortex combines the notebooks you tick into a new one, and compares two to show what they share and what only one has. https://www.kortex-notebooklm.com/features/merge-and-compare-notebooks 1. [Features](/features) 2. Merge and compare notebooks Organize # Merge and compare notebooks Kortex can merge notebooks in Gemini Notebook (formerly NotebookLM). Merge Notebooks combines the notebooks you tick into one new notebook. Compare shows the sources, tags and collections that two notebooks share, and can add what only one has to the other. [Add to Chrome](https://chromewebstore.google.com/detail/kortex/hdapplggdhndkblofffknpmnnnnbncbn) [Follow the tutorial](/tutorials/how-to-merge-notebooklm-notebooks) [![Compare Notebooks in the Kortex Workspace: two notebooks side by side with counts of sources, tags and collections, shared sources highlighted in green, and Sync All, Merge into New and Export Diff buttons.](/media/features/compare-notebooks.webp)](/media/features/compare-notebooks.webp) Compare two notebooks: what they share and what only one has. ## What do Merge and Compare notebooks do? Merge Notebooks combines the notebooks you tick into one new notebook in Gemini Notebook, and can delete the originals. Compare shows what two notebooks share and copies over what is missing. ## What you get - ### One notebook instead of five Put related research into one notebook. Gemini Notebook then answers from all of it together. - ### Keep the originals, or not A Delete originals switch decides if Kortex removes the old notebooks after the merge. Leave it off until you have checked the new one. - ### See the overlap before you merge Compare puts two notebooks side by side with their source, tag and collection counts. Shared sources show in green. - ### Copy only what is missing After a comparison, you can add what only one notebook has to the other. You can sync tags and collections too. ## How do I merge notebooks? **Merge Notebooks** builds a new notebook from the ones you choose. Open it from the sidebar of the Kortex Workspace. Give the new notebook a name. Then tick the notebooks to include. You need at least two. Kortex shows how many notebooks you picked and how many sources the new one will hold. Two choices sit beside the name. **Delete originals** removes the old notebooks after the merge. Add merged notebook to a collection files the result as it is created. Click **Merge** and confirm. The merge cannot be undone, so keep the originals until you have opened the new notebook. ## Is there a source limit? Gemini Notebook limits the sources in a notebook. If a merge goes over that limit, Kortex shows **Merge Incomplete**. It says how many sources were added and lists the ones that were not. ## How does Compare work? **Compare** works on two notebooks. Tick two notebooks, choose **Compare**, then **Compare Selected**. You see both notebooks side by side with their source, tag and collection counts. Sources both have show in green. From there: - add the sources that only one notebook has to the other - **Sync All**, **Sync tags** and **Sync collections** - **Merge into New**, which merges the two - **Export Diff**, which saves the difference ## When to use which Merge when several notebooks are really one topic. Compare when two notebooks overlap and you want to see how, or update one from the other. Use either with [collections](/features/collections-and-folders) to keep the result filed. ## How it works Want every step? [Follow the tutorial](/tutorials/how-to-merge-notebooklm-notebooks). 1. ### Open Merge Notebooks In the Kortex Workspace, choose Merge Notebooks in the sidebar. Or tick notebooks in the Notebooks table and choose Merge. 2. ### Name it and tick notebooks Type a name for the new notebook and tick the notebooks to add. Kortex shows how many sources the new notebook will hold. 3. ### Merge Choose whether to delete the originals, then click Merge and confirm. The merge cannot be undone. 4. ### Compare two notebooks Tick two notebooks and choose Compare, then Compare Selected. Use the buttons to copy what is missing from one side to the other. ## Questions people ask Something we missed? [Ask us](#contact). ### How many notebooks can I merge at once? Tick as many as you need, at least two. Kortex shows how many sources the new notebook will hold before you click Merge. ### Can I undo a merge? No. Kortex warns that a merge cannot be undone. That is why Delete originals is your choice. It is safest to keep the originals until you have checked the new notebook. ### What if the new notebook is too big? Gemini Notebook limits how many sources a notebook can hold. If some do not fit, Kortex shows Merge Incomplete. It says how many sources could not be added and lists them. ### What does Compare do that Merge does not? Merge makes a new notebook from several. Compare looks at two notebooks that already exist and shows what they share. You can copy over only what is missing. ### Does merging copy my tags and collections? Merge has an option to add the merged notebook to a collection. In Compare, Sync tags and Sync collections copy those from one notebook to the other. ### How do I merge NotebookLM notebooks? Open Merge Notebooks from the sidebar of the Kortex Workspace, name the new notebook and tick at least two notebooks. Click Merge and confirm. The merge cannot be undone, so keep the originals until you have checked the new notebook. ## Related features The full reference is in the [Kortex docs](/docs/merge-notebooks). - [Collections and folders Folders for notebooks, with subfolders, colors and pins. Folders for sources and artifacts too.](/features/collections-and-folders) - [Bulk import Add many sources at once from a list of links, your open tabs, an RSS feed, a CSV file or a crawl.](/features/bulk-import) - [Kortex Workspace dashboard One tab for every notebook. A table with filters, columns, dark mode and keyboard shortcuts.](/features/kortex-workspace) [All Kortex features](/features) ## Try it on your own notebooks. 100,000+ people use the Kortex extension. Install it and try merge and compare notebooks on a notebook you already have. [Add to Chrome](https://chromewebstore.google.com/detail/kortex/hdapplggdhndkblofffknpmnnnnbncbn) 100,000+ users, rated 4.5 on the Chrome Web Store.