Privacy First
Uploaded files are automatically and permanently deleted within two hours.
Automatic deletion
Ebook Converter
Convert any ebook into the format your reader needs – EPUB, Kindle (AZW3, MOBI), PDF, DOCX and 20+ more.
-
Free: Convert ebooks online without sign-up or watermarks.
-
Any reader: Output for Kindle, Kobo, Apple Books, Google Play Books, tolino and PocketBook.
-
Privacy: Uploads are deleted after 30 minutes, converted books after 2 hours.
Ebook conversion
Convert ebooks between 25+ formats
Upload an ebook, pick the output format in the dialog and download the converted book. The conversion runs on calibre, the open-source ebook toolkit used by publishers and libraries, so chapters, table of contents, cover and metadata are carried over wherever the target format supports them.
How to use Converter App
1
Upload your ebook
Choose a file from your device or import it from Google Drive. EPUB, MOBI, AZW3, FB2, LIT, PDB, PDF, DOCX, TXT, CBZ and many more are accepted.
2
Choose the output format
A dialog lists the most common targets first – EPUB, MOBI, AZW3, PDF, DOCX, TXT, FB2 – and all other formats one click further.
3
Download the converted book
Most books are ready within seconds. Copy the result to your reader, send it to your Kindle or save it straight to Google Drive.
Key features
calibre engine
Every conversion uses calibre's ebook-convert, the same engine behind the calibre desktop app, including its heuristics for chapter detection and reflow.
Kindle ready
AZW3 (KF8) is the best choice for current Kindle devices and apps; MOBI remains available for very old Kindles. Kindle also accepts EPUB via Send to Kindle.
Structure preserved
Table of contents, chapters, embedded cover and author/title metadata are kept when both formats support them. Reflowable formats stay reflowable.
No DRM removal
Books protected by DRM (for example purchased Kindle titles) cannot be converted – the converter only works with DRM-free files you are allowed to convert.
Experience & privacy
Built for reliable document conversion.
Backed by 10+ years of engineering expertise in large-scale data and scientific computing, it’s built for real-world document workflows that require accurate layout preservation, strict privacy, and dependable, high-level performance.
Trusted by Users
Rated 5 stars on Trustpilot for speed, reliability, and ease of use.
User trust
Academic Use
Referenced in published research and used for interview transcription and qualitative data analysis.
Research use
How the ebook converter works
Behind the upload box runs calibre's ebook-convert, the open-source conversion engine that has been developed since 2006 and is used by readers, libraries and small publishers worldwide. Converter App only adds the web interface: your file is uploaded, calibre reads it into an internal HTML representation, applies its chapter and table-of-contents detection and writes the format you selected. Nothing is re-typed or re-rendered by hand, so the text itself never changes.
Reflowable formats – EPUB, AZW3, MOBI, FB2, LIT, PDB – convert into each other with the best results, because they all describe the book as flowing text with styles. Fixed-layout sources such as PDF need more interpretation; see the FAQ for what to expect.
Choosing the right output format
- EPUB – the open standard. Works on Kobo, tolino, PocketBook, Apple Books, Google Play Books and, via Send to Kindle, on Kindle too. Pick this when unsure.
- AZW3 – Amazon's KF8 format for Kindle devices and apps. Better typography than MOBI.
- MOBI – the legacy Kindle format. Only needed for Kindles from before 2011 or for some older apps.
- PDF – fixed pages, good for printing or reading on a laptop, poor for small screens because the text does not reflow.
- DOCX / RTF / TXT – when you want to edit the text in Word, LibreOffice or a plain editor.
- FB2 – common in Russian-language readers and libraries; keeps structure and metadata.
Tips for better conversions
- Start from the most structured source you have. EPUB → AZW3 is nearly lossless; PDF → EPUB is a reconstruction.
- If a converted book shows chapter breaks in odd places, the source probably used blank lines instead of real headings. Fixing the headings in the EPUB (for example with calibre's editor) before converting gives a clean table of contents.
- Comic archives (CBZ, CBR) convert to PDF or EPUB as page images – choose PDF for tablets and EPUB for readers that support fixed-layout comics.
- Very large books with many images convert more slowly; the progress bar keeps updating until the download is ready.
Limits, privacy and what we don't do
There is no account, no watermark and no daily quota within fair use. Files are processed on servers operated by Converter App and are removed automatically – uploads after 30 minutes, results after 2 hours. We do not remove DRM, and we do not keep copies of your books. If a conversion fails, the most common reasons are a DRM-protected file, a damaged archive or a PDF that contains only scanned images.
FAQ
Frequently Asked Questions
Which ebook formats can I convert?
Input: EPUB, MOBI, AZW, AZW3, AZW4, KFX (DRM-free), FB2, FBZ, LIT, LRF, PDB, PRC, RB, SNB, TCR, TXT, TXTZ, HTML, HTMLZ, RTF, DOCX, ODT, PDF, CBZ, CBR, CBC, CHM, PML and Markdown. Output: EPUB, MOBI, AZW3, PDF, DOCX, TXT, FB2, LIT, LRF, PDB, RTF, SNB, HTMLZ, TXTZ, PMLZ, RB, TCR, OEB and ZIP. You cannot convert a file into the format it already has.
Which format should I choose for my Kindle?
Choose AZW3 for any Kindle sold since 2011 and for the Kindle apps – it supports modern layout features (KF8) and renders better than MOBI. Pick MOBI only for very old devices. If you use Amazon's Send to Kindle service or email, you can also send an EPUB directly; Amazon converts it on their side.
Why does my PDF look odd after converting it to EPUB or MOBI?
PDF is a fixed-layout format: it stores positioned lines, not flowing paragraphs. When calibre turns it into a reflowable ebook it has to guess where paragraphs and chapters begin, so multi-column layouts, tables, footnotes and headers can end up out of order. Text-based PDFs from a word processor convert well; scanned PDFs contain only images and should go through an OCR tool first.
Is the cover, table of contents and metadata kept?
Yes, whenever the target format can store them. EPUB, AZW3, MOBI, FB2 and LIT keep the embedded cover, the chapter table of contents, title, author, language and series tags. Plain formats such as TXT or RTF only keep the text itself.
Can I convert a DRM-protected book?
No. Books bought from Amazon, Kobo, Apple or most other stores are usually encrypted with DRM, and this converter does not remove copy protection. Such a file fails with an error that the ebook could not be read. DRM-free purchases (for example from many independent publishers, Humble Bundle or Project Gutenberg) convert without problems.
What happens to my files?
The upload is transferred over HTTPS and processed on our own servers. Uploaded files are deleted automatically 30 minutes after the upload and converted books 2 hours after they were created. Nobody looks at the content, and there is no account or email required.