MangaSendr and Calibre for manga
Calibre is the free e-book manager many readers already have, and it can convert CBZ and CBR comics. Use it to manage covers and metadata yourself or to keep everything on your computer. Use MangaSendr to get manga sized for your Kindle model, split if needed and sent from any browser, without setting anything up.
We make MangaSendr, so keep that in mind as you read. What we say about Calibre comes from its manual and FAQ, linked at the bottom of this page.
The short answer
Calibre is a free, open-source e-book manager for Windows, macOS and Linux. Version 9.15 came out on September 18, 2026. It converts between dozens of formats, edits metadata and covers, and can email books to your Kindle once you add a mail account in its preferences.
For comics it has a converter with grayscale, border trimming, a right-to-left option for splitting wide pages, and output profiles for several Kindles. It's built mostly around text books, though. KCC's FAQ warns that Calibre doesn't properly support fixed-layout EPUB and MOBI files, which is the kind of file comics need on a Kindle.
MangaSendr only does manga and comics, and only for Kindles. You pick your Kindle once, and each file is converted, split if it's too big for email, and sent.
Calibre and MangaSendr side by side
| Calibre | MangaSendr | |
|---|---|---|
| Cost | Free | Your first volume is free, then $29 paid once or $4.99 a month |
| Install | Desktop app for Windows, macOS and Linux | Nothing to install. It runs in any browser, phone included. Optional app for Mac and Windows. |
| Files it reads | CBZ, CBR, CB7 and CBC comics, plus PDF, EPUB and more than 20 other e-book formats | CBZ, ZIP, image-based EPUB, PDF, JPG, PNG and WebP. CBR only when it's a ZIP inside. |
| Files it makes | EPUB, AZW3, MOBI, PDF, KEPUB and more | A fixed-layout EPUB for your Kindle |
| Sends to your Kindle | Yes, by email, once you set up a mail account in its preferences. Its FAQ suggests a GMX account, which Calibre limits to one book every five minutes. | Yes, by Send to Kindle email, after you approve our address in your Amazon settings once |
| Big volumes | Not split. Over 50 MB, use a USB cable or Amazon's website, which takes up to 200 MB. | Takes files up to 500 MB and splits big ones into parts small enough for email, each with its own cover, named (1 of 3) and so on. Every part is sent for you. |
| Page sizes | Presets for several Kindles, including the Voyage, Oasis and Scribe, or a custom size you type in. No preset for the 2021 and newer Paperwhites or the Colorsoft. | 10 Kindle profiles, from the 6-inch Kindle to the 11-inch Scribe. Kindles only. |
| Reading direction | A right-to-left option for splitting wide pages | Right to left by default, left to right per upload in the web app |
| Color | Grayscale by default, with an option to keep color | Color kept on the Colorsoft and Scribe Colorsoft, grayscale on other Kindles |
| Covers and metadata | Full editing of titles, series, covers and tags, plus metadata download | The first page becomes the cover and the file name becomes the title |
| Open source | Yes (GPL v3) | No |
When Calibre is the better pick
- You want to manage a library. Calibre keeps manga next to your novels, with series, tags, covers and metadata you can edit or download. MangaSendr keeps a short history of what you sent, not a library.
- You want everything to stay on your computer. Calibre converts on your machine. MangaSendr uploads the file, converts it on our server and deletes it within 24 hours of sending.
- You read on more than a Kindle. Calibre converts for Kobo, PocketBook, Nook and others and can copy books over USB. MangaSendr only emails Kindles.
- You convert a few volumes a year and don't mind settings. Our Calibre settings guide for manga lists the options that matter.
- You don't want to pay. Calibre is free, and if your comics are under 50 MB, its email sharing gets them to your Kindle.
When MangaSendr fits
- You have a current Kindle. MangaSendr has page sizes for the 7-inch Paperwhite and Colorsoft (1272 x 1696) and the 11-inch Scribe (1986 x 2648), so you don't have to look up a custom size.
- Your volumes are over 50 MB. They're split into parts small enough for email, each with its own cover, and all of them are sent.
- You want the book to turn like printed manga. MangaSendr builds a fixed-layout EPUB, one screen per page, set to turn right to left.
- You're away from your computer. The web app works in any browser, including a phone's.
- You'd rather not open an app for each new volume. The optional Mac and Windows app checks a folder about once an hour and sends new files to your Kindle.
Using both
Calibre and MangaSendr do different jobs, so they sit well together: Calibre for novels and for keeping the library tidy, MangaSendr for getting manga onto the Kindle.
One caution from KCC's FAQ applies to any comic EPUB: don't open a fixed-layout file in Calibre to change its title or cover, because that can break its layout and page numbers. Rename the original file before you send it instead. MangaSendr uses the file name as the title.
Questions
Can Calibre convert CBZ to EPUB for a Kindle?
Yes. Calibre reads CBZ, CBR, CB7 and CBC files and converts them to EPUB, AZW3 or MOBI. Pick a Kindle output profile or type a custom image size, then set grayscale, trimming and right-to-left splitting. Our Calibre settings guide lists the options that matter for manga.
Can Calibre send books to my Kindle?
Yes. Add a mail account under Preferences, in Sharing books by email, and approve that address in your Amazon settings. Amazon's 50 MB email limit still applies, and Calibre doesn't split files.
Why does KCC say not to use Calibre?
KCC's FAQ says Calibre doesn't properly support fixed-layout EPUB and MOBI, so changing a KCC-made file in Calibre, even just its metadata, can break the formatting and page numbers.
Does MangaSendr edit metadata like Calibre?
No. The first page becomes the cover and the file name becomes the title, so a clear name such as Series Name 01.cbz gives you a tidy entry in your Kindle library.
What does MangaSendr cost?
Your first volume is free and you don't need a card. After your free volume, the license covers multi-file sending, splitting, automation and sending from any device, with delivery included. It's $29, paid once, with a 14-day money-back guarantee, or $4.99 a month. Pricing has the details.
Sources
Each source was checked on .
- Calibre FAQ: supported formats, emailing books to a Kindle: manual.calibre-ebook.com/faq.html
- Calibre manual: ebook-convert comic input options and output profiles: manual.calibre-ebook.com/generated/en/ebook-convert.html
- Calibre release notes: version 9.15, September 18, 2026: calibre-ebook.com/whats-new
- Calibre source code and license (GPL v3): github.com/kovidgoyal/calibre
- KCC README: features, input and output formats, device profiles, FAQ: github.com/ciromattia/kcc
- Amazon: Learn How to Use Your Send to Kindle Email Address (25 attachments, 50 MB per email): www.amazon.com/gp/help/customer/display.html?nodeId=G7NECT4B4ZWHQ8WV
- Amazon: Learn About Sending Documents to Your Kindle Library (200 MB on the web, supported files): www.amazon.com/gp/help/customer/display.html?nodeId=G5WYD9SAF7PGXRNA
More comparisons
- All the tools in one table: Send to Kindle, KCC, Calibre and MangaSendr side by side.
- MangaSendr and KCC
- MangaSendr and Send to Kindle
- How MangaSendr works, from your file to your Kindle library.
Send one volume and compare for yourself
You don't need a card, and there's nothing to install. After your free volume it's $29 once, not per volume, and it doesn't renew.