CBR vs CBZ: The Difference, and Which One You Should Use
CBR is a renamed RAR, CBZ a renamed ZIP — same images inside. Why CBZ is the better choice today, and how to convert either for a Kindle or Kobo.
CBR and CBZ hold exactly the same thing — a stack of page images — and differ only in the archive wrapped around them: CBR is a RAR archive renamed, CBZ a ZIP archive renamed. Your reader shows identical pages either way. The practical difference is that ZIP is an open format anyone can create and read freely, while RAR compression is proprietary. That's why CBZ has become the default, and why, given the choice, CBZ is the one to pick.
Short version
Same images, different archive: CBR = RAR, CBZ = ZIP. Reading either is easy — nearly every comic app opens both. Creating is where they differ: anyone can make a CBZ (zip the images, rename), while making a CBR needs RAR software. Prefer CBZ. And if the goal is reading on a Kindle or Kobo, convert either one to EPUB at mangaconverter.com — e-readers don't open CBR or CBZ natively.
What the letters mean
The "CB" family is just "Comic Book" plus the archive type:
- CBZ — Comic Book ZIP
- CBR — Comic Book RAR
- CB7 — Comic Book 7-Zip (rarer; see What is a CB7 file)
Rename a .cbz to .zip and it opens in any archive tool; same for
.cbr and .rar. There is no comic-specific data beyond the images and,
sometimes, a ComicInfo.xml metadata file. Page order comes from
alphabetical filenames.
Where CBR and CBZ actually differ
Openness. ZIP is a documented open standard; free tools on every
platform create and extract it. RAR's compression is proprietary — reading
is widely licensed, but creating a RAR requires WinRAR or the rar tool.
That asymmetry alone decides the format war: new releases and tools
overwhelmingly use CBZ.
Compression. RAR can compress slightly better in general use, but comic pages are already-compressed JPEG or PNG images — no archive format squeezes meaningful extra size out of them. In practice CBR and CBZ files of the same comic are nearly identical in size. Compression is not a reason to choose either.
Compatibility. Almost all comic readers open both. The gap appears at the edges: some open-source tools, library servers and scripts handle ZIP natively but need extra libraries for RAR. CBZ never has this problem.
Converting between them
CBR to CBZ is a repack, not a re-encode: extract the RAR, zip the images,
rename to .cbz. Image quality is untouched because the images themselves
are never modified. There's rarely a reason to go the other direction —
making CBR files requires proprietary software for no benefit.
Neither one works on an e-reader
The comparison most people actually need: Kindle, Kobo and reMarkable devices open neither format. If your destination is an e-reader, the right move isn't CBR-vs-CBZ, it's converting to EPUB (or KEPUB for Kobo) with pages sized for your screen. The open-source Kindle Comic Converter engine (github.com/ciromattia/kcc) does exactly this, and MangaConverter runs it in your browser — both CBR and CBZ go in, a device-fit EPUB comes out, with a live preview first.
Direct routes: CBR to EPUB, CBZ to EPUB, CBR to Kindle, CBZ to Kobo.
Which should you keep in your library?
If you archive comics long-term, standardize on CBZ:
- Open format — readable decades from now without licensed software.
- Best tool support, from readers to metadata editors to servers.
- Nothing lost in the switch; repacking is lossless.
Keep CBRs you already have if everything you use opens them — there's no urgency — but create CBZ going forward (how-to: make a CBZ file), and convert to EPUB per device when it's time to read on e-ink. More on the format's details in What is a CBZ file.