Step 1: Transfer your EPUB files using the button above or by slide and deposit.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Retrieve your converted AZW3 files.
EPUB to AZW3 Conversion FAQ
Is the EPUB to AZW3 converter free?
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Yes. One conversion an hour is free, with no account needed, for a file within the free size limit. A paid plan removes the hourly limit and the size limit, and lets you add several files to one job. AZW3 is Kindle Format 8, which Amazon introduced in 2011 to replace the ageing MOBI format.
Why does my EPUB file refuse to convert?
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DRM, in almost every case. A protected EPUB is encrypted and tied to an account, and no converter can decrypt it — ours included. Files you created yourself, or bought from a DRM-free store, convert without any trouble at all. EPUB has no fixed pagination, so page numbers are meaningless, and complex layout — tables, equations, multi-column — degrades badly.
How big an EPUB file can I convert to AZW3?
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Free conversions have a size limit per file, set by the type of file, and the page tells you when a file is over it. A paid plan removes that limit, so much larger files can be converted.
Can I convert many EPUB files to AZW3 at once?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
Does the EPUB to AZW3 converter work on phones and tablets?
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Yes — the UI is responsive and the conversion pipeline runs server-side, so mobile devices upload-then-download just like desktops. iOS and Android browser file pickers (camera roll, Files app) work end-to-end.
Which browsers does the converter support?
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Chrome, Firefox, Safari (15+), Edge, and Opera. The converter uses standard `<input type="file">` upload — no WebAssembly or PWA dependency — so even older browsers work to upload an EPUB and download the AZW3.
Are my EPUB files kept private?
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Yes. Uploaded EPUB files are processed on our own conversion servers, no person reviews them, and they are never shared. The upload and the converted AZW3 are both deleted automatically about 24 hours after the conversion, which leaves time to download the result. See /privacy/ for the full policy. EPUB reflows text to any screen size and any font size, which is what makes it readable on a phone as well as an e-reader.
What if the AZW3 download does not start automatically?
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Disable any pop-up blocker, then click the download button manually. The result link stays active for 24 hours, so if your network drops mid-download you can retry from the result page without re-uploading the EPUB.
How long does EPUB to AZW3 conversion take?
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It depends on the size and length of the file. Small documents and images are usually ready quickly. Long videos take the longest, because most video conversions re-encode every frame. AZW3 supports embedded fonts, drop caps, fixed-layout pages and proper CSS, so illustrated and technical books survive it. AZW3 is Amazon-only, and DRM-protected purchases cannot be converted by any tool.
Do I need to install software to convert EPUB to AZW3?
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No — the converter runs entirely in your browser plus our servers. No desktop install, no plugin, no browser extension. Just upload, wait briefly, download the AZW3.
