How to Convert Manga With Calibre
Calibre converts comics. That is worth saying plainly, because plenty of pages pretend otherwise: Calibre ships a Comic Input plugin that reads CBZ, CBR and CBC, and it does real page work. By default it converts pages to greyscale, normalizes contrast, sharpens, trims borders and splits double-page spreads into single pages. It also has a dedicated manga option for right-to-left reading. If you already run Calibre for your library, you do not need a second tool to get a readable file.
↑ Upload and configure in our Studio
What trips people up is that Calibre gives you flags rather than a target. The comic options are spread across a conversion dialog, the screen size comes from a separate output profile setting, and you find out whether the result reads well only after the file is on your device. This page walks the settings that actually matter, using their real names, so the first conversion lands closer than the fifth.
Then, if you would rather not install anything, the same job runs in this browser tab with a live preview of the converted pages. Both routes are legitimate. Pick by which friction you mind less.
- Files auto-delete after 24 hours
- No install, runs in any browser
- Free to use
- The genuine open-source KCC engine
Converting a manga volume in Calibre
Add the file and set the output profile first
Add your CBZ or CBR, then open Preferences and set the output profile to your reader before converting. Calibre's manual is explicit that "the output profile also controls the screen size. This will cause, for example, images to be auto-resized to fit the screen." Get this wrong and every later setting is tuned against the wrong panel.
Turn on the manga option for right-to-left
In the comic input section, enable the right-to-left option (--right2left on the command line). Calibre documents it as "used for right-to-left publications like manga. Causes landscape pages to be split into portrait pages from right to left." Without it, split spreads come out in western reading order and the panels land out of sequence.
Decide about trimming and spread splitting
Both are ON by default. Border trimming can be disabled (--disable-trim) and Calibre warns that "for some comics, trimming might remove content as well as borders." Spread splitting is also default; the --landscape flag means "don't split landscape images into two portrait images", so turn it on when you want spreads kept whole on a big screen.
Choose colour and image processing
Calibre greyscales, normalizes and sharpens unless told otherwise: --dont-grayscale keeps colour (worth it on a Colorsoft or a tablet), --dont-normalize disables the contrast pass, --dont-sharpen disables sharpening, and --despeckle reduces noise on rough scans at the cost of processing time. There is also --no-process to skip image handling entirely.
Convert, transfer, and check on the device
Run the conversion, send it to your reader, and look at a spread and a dense dialogue page. If something is off, the loop is: change one flag, reconvert, transfer, look again. That loop is the real cost of the desktop route, and it is the specific thing the browser version below removes.
Calibre on your desktop vs this converter in your browser
| What you compare | Calibre (desktop) | MangaConverter (browser) |
|---|---|---|
| Getting started | Download and install Calibre on Windows, macOS or Linux | Nothing to install. Opens in any browser, phones, tablets and Chromebooks included |
| Comic page processing | Comic Input plugin: greyscale, contrast normalize, sharpen, trim, spread splitting, right-to-left | The open-source KCC pipeline: manga mode, spread handling, borders, upscaling, gamma |
| Choosing the target | An output profile setting plus individual comic flags | A device profile picked by name, at that device's true resolution |
| Seeing the result | Convert, transfer to the device, then look | Live page-by-page preview in the browser before you convert |
| Managing a library | A full library manager: metadata, series, covers, device sync, a plugin ecosystem | Not a library manager. It converts files and hands them back |
| Working offline | Converts locally, fully offline | Needs a connection; files upload to our servers and auto-delete after 24 hours |
| Price | Free, open source | Free tier for regular use; paid plans for heavy use |
Where these settings come from
Every flag named on this page is quoted from Calibre's own ebook-convert documentation and its Comic Input plugin, not from our testing. We have deliberately made no claim about how Calibre's output looks compared to ours, because that is a comparison we have not run.
Command line, if you prefer it
Calibre ships ebook-convert, so the whole thing scripts: pass your input and output files followed by the comic options above. That is genuinely the fastest route for a large batch on a machine you own, and no browser tool replaces it.
The rest of the picture
For the settings reference on its own see our Calibre comic conversion settings page. For how this converter compares as a focused alternative, see the Calibre alternative for manga page. If you also looked at Kindle Comic Converter, the KCC pages cover that side.
Frequently asked questions
Can Calibre convert CBZ and CBR at all?
Yes. Calibre has a Comic Input plugin that reads CBZ, CBR and CBC and converts them to EPUB, MOBI, AZW3 and the rest. Anyone telling you Calibre cannot handle comics has not opened the conversion dialog. The question is not whether it works, it is how much setup you want to do.
Does Calibre handle right-to-left manga?
Yes, through the right-to-left option (--right2left), documented as "used for right-to-left publications like manga. Causes landscape pages to be split into portrait pages from right to left." It is off by default, so you must set it yourself for a Japanese-order volume.
Why did my spreads get cut in half?
Because splitting is the default. Calibre splits landscape images into two portrait pages unless you pass --landscape, which is documented as "don't split landscape images into two portrait images". On a Scribe or a tablet you often want the spread intact; on a 6 inch screen you usually do not.
Why does my manga look wrong even after converting?
The most common cause is the output profile. Calibre sizes images to the profile's screen, so a file converted against the wrong device is fitted to the wrong panel. Set the output profile to your actual reader before you convert, not after.
So why use this converter instead of Calibre?
Three reasons, none of them about Calibre being bad at comics. You may not want to install a desktop application for one conversion. You may be on a phone, an iPad or a locked-down work machine where you cannot install one. And you may want to see the converted pages before committing, rather than after a transfer. If none of those apply and you already run Calibre, keep using Calibre.
Should I keep using Calibre for my library?
Yes, and we mean it. Calibre is the best free library manager there is: metadata editing, series handling, cover management, device sync and a deep plugin ecosystem. This converter does one job and does not try to be a library. Plenty of people convert here and file the result in Calibre, which is a perfectly sensible setup.
This converter runs the genuine open-source Kindle Comic Converter (KCC) engine in the cloud. We name the engine because it earned its reputation, and we add the hosting, the device profiles and the live preview around it.
KCC on GitHubNo install, device profiles by name, preview before you convert