File & conversion tools / Calibre
Calibre
calibre: The one stop solution for all your e-book needs. Comprehensive e-book software.
Where it stands
3.3 / 5
Signals score
Not a hands-on test
Based on 3 of 3 signals
- Website health3.6 / 5 · weight 50%
Measured from the tool's public website
- Facts stated2.6 / 5 · weight 30%
How many of the five facts the tool's own pages state
- Community4.1 / 5 · weight 20%
What people said in public discussions
Built only from what we can measure or quote without using the tool. How ranking works
Rank by signals
We have not run our own hands-on test on Calibre yet. Facts checked 2026-11-01. How tests work
Disclosure: agathox makes some of the tools listed here. They are labelled and scored by the same method as every other tool.
Should you use Calibre?
A quick read built only from what the tool's own pages state and from our tests, not from opinion. Facts checked 2026-11-01.
A good fit if…
Nothing is clearly stated yet.
Check first
- Its pages do not state: pricing, signup, watermark. Check on the tool's site before you rely on it.
Does: Ebook converter
Measured signals
3.6 / 5 · measured 2026-11-08Read automatically from Calibre's public website: how reliable, secure, private and open the site is. This is not a test of how well the tool does its job. How this is measured
- Reliability5 / 5The page answered and finished downloading in 92 ms.
- Security2 / 50 of 5 protective headers set.
- Privacy4 / 51 third-party tracking service found: Google Analytics.
- Transparency3 / 5Links a privacy policy; no pricing page linked.
Community feedback
4.1 / 5 · 79 commenters82% of the 79 people whose comments we could classify were positive. Read automatically from public Hacker News threads about Calibre; the classifier is simple and can misread sarcasm, so check the threads. How this works
- Positive
“>as simple as uploading it to my hosted instance of calibre-web, and then next time I pick up my kobo it will automatically download it. Wow, sounds really nice, you got my attention. My stack to achieve the same result…”
Read in the thread - Positive
“I don't understand this hypercritical way of looking at things, especially considering how powerful and useful Calibre is. I plugged in a very old e-reader to my computer and tried a variety of things to put books on it;…”
Read in the thread - Critical
“An issue in the past was that books loaded into Kindles through Calibre appeared as 'personal documents' rather than as a 'book' in the Kindle, upsetting causing the reading state sync to not work if you were reading the…”
Read in the thread - Critical
“Personally I never participated in spreading that, but I absolutely was swayed by the negative comments to avoid touching Calibre. I already find myself fact-checking a lot of things given how much bullshit people…”
Read in the thread
Threads: Calibre 4.0 (2019, 302 comments) · Calibre 5.0 (2020, 268 comments) · New in Calibre 6.0 (2022, 214 comments) · Calibre – E-Book Management (2021, 168 comments)
- Free tier
- Not stated. The home page asks for optional contributions and offers downloads for each operating system; no price is given.
- Paid plan
- Not stated.
- Signup
- Not stated.
- Watermark
- Not stated.
- Where files go
- Privacy page says calibre and its website collect no information about users or visitors, apart from aggregate usage figures. It does not say how files are processed.
From the tool's own pages, checked 2026-11-01. Sources: Home page, Privacy. Prices and limits change; check the tool before you rely on them.
Get an email if Calibre changes
We check its official pages every week. If they change, we tell you, so you can see if the price or limits moved. No other email, and one click stops it.
Are you the maker of Calibre? Link to this page
Copy this into your site. The link goes to this page, and it does not change any score.
<a href="https://agathox.com/tools/calibre">Calibre on agathox: compared and tested</a>
Tasks and scores
- Ebook converterNot tested yet
Similar tools
Top signals in Ebook converter.
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