What is a CBZ file, and how do you read one?

What a CBZ is

Inside a CBZ are the comic's pages as image files, named so a reader shows them in the right order. Some CBZ archives also carry ComicInfo.xml, a file of details about the comic, which is covered below.

The name is the interesting part. The format underneath is plain ZIP, and PKWARE's ZIP specification says the .zip extension is not required and lists other names in use for the same format (.jar, .docx and others); programs identify a ZIP from the records inside the file. A .cbz name works the same way: the extension is not required, and comic readers use the name to know to open the archive as a comic.

The letter after CB names the archive inside. CBZ is a ZIP. CBR is a RAR, and rarlab calls RAR the native format of WinRAR. CB7 is a 7z, and 7-Zip is the archiver that packs and unpacks 7z. Two more siblings exist, CBT and CBA. None of the reader home pages we read today names them.

Formats and platforms change; the linked pages have the current wording. Checked 2026-10-01.

CBZ vs CBR

Both hold the same thing: page images in reading order. The difference is the container. ZIP is an open format, and PKWARE permits its specification to be used for products that read and write ZIP files, subject to the document's terms. rarlab's licence calls the RAR compression algorithm proprietary, and rarlab's own software creates RAR archives. Other tools, 7-Zip among them, open RAR; 7-Zip's licence says its RAR decompression engine was developed using source code of rarlab's unRAR program.

RAR does have real advantages, and rarlab lists them: multivolume archives, solid mode and recovery records to repair an archive even in case of physical data damage. They help you build and mend archives. CBR offers no reading advantage today.

So which one should you keep? CBZ. Creating RAR archives takes WinRAR or rarlab's RAR command line, while converting CBR to CBZ copies the page files into a new archive, so there is nothing to lose and no reason to keep the copy that fewer tools can open.

CBZ vs PDF for comics

In a CBZ the pages stay the image files they are; a PDF is a document format. For a comic that is only page images, CBZ is the simpler container. Comic readers are built around it: one page at a time, tap to turn.

A PDF is the better choice when you want to print the comic, or when the person you are sending it to will only open PDFs. Panels and Sumatra PDF both list PDF among their formats, so a PDF collection has a home on those apps.

How to open a CBZ on Windows, Mac, Linux, Android and iPhone

Any unzip tool can open a CBZ to look inside; a comic reader is what turns them back into pages. These are the readers whose home pages we read today, and what each site says it runs on and reads.

Each reader's own home page is the final word on its platforms and formats. Checked 2026-10-01.

How to make a CBZ, and how to convert a CBR

The steps are the same for a folder of page images and for a CBR you want to convert. 7-Zip unpacks RAR and packs ZIP; WinRAR unpacks RAR and ZIP and creates RAR and ZIP archives. One tool does the whole conversion.

1. Get the pages as image files. For a CBR, unpack the RAR first; for a folder of images, you are already there.
2. Check the page order by file name before you zip anything.
3. Zip the page files. Select the images themselves, not the folder above them. Compressing them further buys almost nothing: the pages are images, which are already compressed, and the ZIP specification allows files to be stored uncompressed, which is the right setting here.
4. Rename the .zip to .cbz. That is the whole trick: the ZIP specification says the extension is not required, and the format is identified from the records inside the file.

Converting this way copies every page file as it is, so nothing is lost in the conversion. The reverse, a CBZ turned into a CBR, needs RAR software and buys you nothing.

Once your comics are CBZ files, What's the cheapest S3-compatible storage for a comic library? covers what a library costs to keep in storage you own, and What is WebDAV, and which drives support it? covers reading one from a drive instead.

ComicInfo.xml: the details inside the archive

ComicInfo.xml is an optional file at the root of the archive with the comic's details: title, series, number, writer, penciller, genres and more. It came from ComicRack, which the Anansi Project says is no longer developed, and the project now documents the schema and where it should go next, with Komga, Kavita and Codex among its supporters.

Which apps read it is worth checking rather than assuming, because the file is only useful where the app looks for it. From the documentation we read today:

• Komga gathers metadata from a local ComicInfo.xml file inside a CBZ or CBR, down to the writer, penciller and cover artist.
• Kavita uses one for comics and manga, and says the file must be named ComicInfo.xml and sit at the root of the archive.
• YACReaderLibrary lists ComicInfo.xml among the ways it organizes a collection.
• Easemic reads it too: when a CBZ carries one, the comic's details (title, writer, penciller, genres) come from it into your library.

A CBZ without ComicInfo.xml is still a perfectly good comic. The file adds the details a library can sort and search by, so it is worth adding when you make an archive yourself. When a whole collection needs this treatment, How do you organize a digital comic collection? covers the folders, the tagging and where the library lives.

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