What is the CBZ file format?
Files with .cbz store compressed digital comic books. .cbz uses ZIP archive compression. Comic books are comprised of page images whose reading order is determined by filename sort - pages must be zero-padded (e.g. 001.jpg, 002.jpg) to sort correctly. .cbz archives may also contain subfolders that organize stored images.
Most common image formats used inside .cbz are:
- Lossy JPEG,
- Lossless PNG,
- GIF,
- BMP,
- TIFF.
Additional information can be stored as archive comments or in an optional ComicInfo.xml metadata file. While the format has no official standard, the community-maintained ComicInfo schema (now maintained by the Anansi project) covers such information as:
- Author and publisher details,
- Table of contents,
- Separate text layers for translations.
.cbz files are chiefly used for storing comic books, though the format was originally conceived as a simple method for storing sequential image files, popularised by the CDisplay reader around 2002. Because .cbz is essentially a ZIP archive, its contents can be accessed using any archive manager that supports ZIP compression - simply renaming the file to .zip is enough. However, .cbz archives are best viewed using dedicated comic book readers such as CDisplayEx, YACReader, or MComix.
The comic book archive family includes several related formats that differ only in their compression algorithm: .cbr uses RAR compression, .cbt uses TAR, and .cb7 uses 7-Zip. .cbz is generally preferred among them because ZIP is an open format natively supported on every major operating system. When shared over the internet, .cbz files use the MIME type application/vnd.comicbook+zip.
Security & safety
RISK: LOWA CBZ is passive data - a bundle of images - and cannot execute. The realistic risk is the source, not the format: scanned comics from piracy sites may carry mislabelled files or, rarely, a ZIP that hides a non-image payload. Inspect with 7-Zip before trusting an unexpected CBZ, and be aware that ordinary comics are copyrighted, so distribution legality depends on where you got it.
Format details
in a nutshellPrograms that open CBZ files
Windows4 apps
GonVisor
Free Open the .cbz to read; legacy Windows comic viewer (db 'recommended', still downloadable but no longer actively developed). 
7-Zip
Open-source Right-click > 7-Zip > Open archive to view/extract the page images (a CBZ is a ZIP). 
CDisplayEx
Free Double-click the .cbz; CDisplayEx is the modern successor to the original CDisplay reader. 
YACReader
Open-source Open the .cbz (or add its folder to the YACReader Library) and read page by page. 
macOS2 apps
Simple Comic
Open-source Open the .cbz; lightweight macOS comic viewer (replaces the abandoned 'Comical'/'Sequential'). 
Linux3 apps
Android2 apps
Tachiyomi/Mihon (local)
Open-source Place CBZ files in a local source folder and read them in the library.
Panels
Freemium Import the .cbz into Panels (via Files/cloud) and read; modern iOS/iPadOS comic reader. Technical details
deep spec| Container format | Standard ZIP archive; magic bytes `PK\x03\x04` (hex 50 4B 03 04) at offset 0, identical to any `.zip` file |
| Byte order | Little-endian, per ZIP specification |
| Compression per entry | DEFLATE supported; page images are usually stored uncompressed (STORED method) because JPEG and PNG are already compressed |
| Page ordering | Determined by filename sort order; pages must use zero-padded names (e.g. `001.jpg`, `002.jpg`) to sequence correctly |
| Supported image types | JPEG, PNG, GIF, BMP, TIFF; JPEG and PNG dominate in practice |
| Metadata file | Optional `ComicInfo.xml` following the Anansi project schema (v2.0/v2.1); covers title, author, publisher, series number and genre |
| Integrity checking | Per-entry CRC-32 checksum inherited from ZIP; no comic-specific signature or hash |
| MIME type | `application/vnd.comicbook+zip`; also recognised as `application/x-cbz` and `application/zip` |
| Typical file size | 10 MB - 400 MB per issue; dominated by image resolution and whether pages use JPEG or PNG |
| Color depth | Inherited from embedded page images; typically 24-bit JPEG or 8-bit/24-bit PNG |
| Encryption | ZIP password encryption is technically possible but rarely used; most comic readers do not support encrypted `.cbz` files |
| Maximum entries | 65,535 files (standard ZIP); ZIP64 extension removes this limit, far above any real comic's page count |
| Platform support | Windows, macOS, Linux, Android, iOS; natively extractable on all major OS by renaming to `.zip` |
| Origin convention | Popularised by the CDisplay reader (~2002); no governing body - a community convention maintained by readers and distributors |
| Released | Early 2000s; CDisplay reader (2002) established the .cbz convention |
| Latest version | No versioned spec - it is plain ZIP; optional ComicInfo.xml (ComicRack/Anansi) metadata schema |
| Open standard | Yes · royalty-free |
| Specification | github.com |
CBZ conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about CBZ files.
