Guides · 5 min read
CBZ, CBR, EPUB or PDF: which comic format for your e-reader
A plain-language comparison of the common comic and manga file formats — CBZ, CBR, EPUB, PDF and images — and which one to use for Kindle, Kobo, Boox and reading apps.
Comic files come in an alphabet soup of formats, and the differences matter more on an e-reader than on a computer. Here is what each one actually is, and when to use it.
CBZ — the comic archive
A CBZ is simply a ZIP file full of images, renamed with a .cbz extension. The pages are ordered by filename. It is the de facto standard for digital comics because it is open, lossless, and trivially easy for apps to read. If you use a dedicated comic reader (like Panels, Chunky, KOReader or Tachiyomi-style apps), CBZ is usually the best choice.
CBR — the same idea, different zipper
A CBR is the same concept but built on a RAR archive instead of ZIP. It reads identically, but RAR is a proprietary format, so some tools and servers can't open it. Many files that end in .cbr are actually ZIP archives that were simply renamed — TomoRead detects the real format by inspecting the file, not just its extension, so a mislabelled file still converts. If you're choosing, prefer CBZ over CBR; there's no quality benefit to CBR.
EPUB — for e-reader libraries
EPUB is the native ebook format for Kobo, and it works on Kindle too. For comics you want fixed-layout EPUB, where each page is a full image at a set size, rather than reflowable text. This is the format that slots cleanly into a device's library with a cover and proper page turns. Choose EPUB when you want the comic to live alongside your books rather than in a separate app.
PDF — the universal fallback
Everything opens a PDF. It's the safest choice if you're not sure what your device supports, or if you're reading on a phone or tablet. The downside is that PDFs have fixed page dimensions, so a PDF sized for a big screen can look small on a little one — which is exactly why converting with the right device profile matters. A PDF built for your specific screen is excellent; a generic one is mediocre.
A folder of images
Sometimes you just want the numbered JPGs or PNGs — to re-order pages by hand, feed them into another tool, or archive them. TomoRead can output a ZIP of numbered images for exactly this.
Quick recommendations
- Kindle: EPUB (fixed-layout) or PDF.
- Kobo: EPUB (fixed-layout).
- Boox and other Android e-ink: CBZ in a comic app, or EPUB/PDF in the library.
- A comic reading app on any device: CBZ.
- Phone or tablet, no special app: PDF.
Format only decides the container. Readability on a small screen comes from how the pages inside are sized and split — that's the job of Smart conversion, whichever format you pick.