Why Send to Kindle Doesn’t Work with Some PDFs (and How to Make Sure They Arrive)

If you tried to send a PDF to your Kindle using Send to Kindle and it never arrived, or Amazon emailed you saying the file was rejected, you’re not alone. This can happen for several reasons. Here’s why Send to Kindle might not work with certain PDFs—and what you can do to make sure your files reach your device and look right.

Why does Send to Kindle reject some PDFs?

Send to Kindle is Amazon’s system for sending documents to your Kindle online—through the website, desktop app, mobile app, or by email. While it accepts PDFs, sometimes files don’t arrive or are rejected. Here are the most common reasons:

• The file is too large: The limit is 200 MB per file. If your PDF is bigger, Send to Kindle will reject it.
• The format isn’t supported: Send to Kindle accepts PDF, EPUB, DOC, DOCX, TXT, RTF, HTML, and images. It does not accept AZW3 or MOBI. If your file has an unusual extension or is damaged, it won’t process it.
• Email issues: If you’re sending PDFs by email, make sure you’re using an approved email address and the correct @kindle.com address. If there’s a problem, Amazon will notify you by email.

Why does my PDF arrive but look wrong?

Even if your PDF makes it to your Kindle, it might not display well because of how Amazon handles PDFs:

• The PDF displays as a fixed page: Kindles show PDFs as full page images. On a Kindle screen, an A4 page will appear much smaller, and the text can be tiny. You’ll need to zoom or rotate, but you can’t adjust font size or formatting.
• Failed automatic conversion: If you send the PDF by email with “convert” in the subject, Amazon tries to convert it to reflowable text. This works for simple documents or novels, but often fails with notes, titles, columns, or scanned PDFs—mixing up order, losing the table of contents, or missing sections.

For more on how PDFs look on Kindle and ways to improve it, see this guide.

How can you make sure your PDF arrives?

1. Check the file size and format: Make sure your PDF is under 200 MB and uses a supported extension.
2. Send from an approved email: If you’re using email, confirm your address is authorized on Amazon and you’re using the right @kindle.com address.
3. Try sending without “convert”: If the converted PDF looks wrong, send it without “convert” in the subject so Kindle displays it as a fixed page (though the text may be small).
4. Convert the PDF to reflowable text first: If you want adjustable fonts and better formatting, it’s best to convert your PDF to EPUB before sending. Send to Kindle treats EPUBs as books and keeps the table of contents if the EPUB has one. Tools like Legible convert PDFs online for free and let you review the result before downloading.
5. Transfer by cable if it still doesn’t work: If Send to Kindle keeps rejecting your file, you can transfer the converted book as AZW3 by cable. See this guide for step-by-step instructions.

What if my PDF is a scan or has columns?

Scanned PDFs (images) or documents with columns often cause problems with Amazon’s conversion. In these cases, use a converter that does OCR (text recognition) and keeps the reading order and headings, like Legible. This way, you can turn the PDF into a real Kindle book with adjustable text and a generated table of contents, then send it as EPUB via Send to Kindle or as AZW3 by cable.

More resources

• Send to Kindle with PDF: What “convert” Really Does and When to Use It
• How to Send a PDF to Kindle Without Needing to Zoom
• How to Convert a PDF to Kindle Online for Free (and Read It Better)

In short: Send to Kindle rejects PDFs for size or format issues, and sometimes converts them poorly. If you want your book to arrive and be easy to read, try converting it to EPUB or AZW3 first. If it still doesn’t work, transfer it by cable.