I’ve used every method Amazon offers to get books onto a Kindle, and each one has its own quirks. Depending on what you’re sending and where you are, some approaches work dramatically better than others. Here’s the real rundown.
1. Send to Kindle web page
The simplest option that nobody seems to know about: just go to amazon.com/sendtokindle. Drag a file onto the page, signed into your Amazon account, and it shows up on a Kindle within a minute or two over Wi-Fi. No app install, no email configuration. I use this more than anything else.
2. The desktop app (Send to Kindle for PC/Mac)
Amazon has a dedicated app for Windows and macOS. Once installed, you can right-click any supported file and choose “Send to Kindle.” It also adds a virtual printer, so you can “print” any document directly to a Kindle library. The Mac version is a bit less polished than the Windows one — on macOS I’ve had it occasionally fail to recognize the device until I quit and reopened. Still, for batch-sending a pile of DRM-free books, it’s the fastest method.
3. Email to Kindle
Every Kindle gets its own @kindle.com address. You can find yours under Settings → Your Account → Send-to-Kindle Email. Attach a file to an email, send it to that address, and Amazon converts and delivers it. The catch: emails are only accepted from addresses on your Approved Personal Document E-mail List (same settings page). I can’t count how many times I’ve sent something only to get a bounce-back because I was emailing from a new address I forgot to whitelist.
4. Chrome extension
The official Send to Kindle Chrome extension turns any web article into a clean, readable document on a Kindle. It strips navigation, ads, and sidebars, leaving just the text and images. It’s not perfect — code blocks and deeply nested tables sometimes get mangled — but for long-form articles and blog posts it’s excellent.
5. iOS / Android share sheet
On a phone or tablet, the Kindle app registers itself as a share target. Open a PDF or EPUB in any app that supports sharing (Files, Safari, your email client), tap Share, and select the Kindle app from the list. It’ll ask whether to add the file to a library and which device to deliver to. This is my go-to when someone emails me a document and I want it on my Kindle without touching a computer.
Format wars: EPUB vs MOBI
In late 2022, Amazon announced that Send to Kindle would stop accepting MOBI files and standardize on EPUB. Today, EPUB is the preferred format. MOBI files sent through the service are still accepted for now, but Amazon explicitly states they won’t support newer Kindle features in MOBI documents. If you’ve got an old Calibre library full of MOBI files, convert them to EPUB.
That said, the conversion isn’t flawless. Some EPUBs — especially ones with complex CSS, embedded fonts, or fixed layouts — lose formatting during Amazon’s server-side conversion. Tables can break, drop caps may disappear, and line spacing sometimes goes haywire. I always preview the first few pages on my Kindle after sending. If it looks wrong, side-loading via USB with the original file in the /documents/ folder preserves formatting that Send to Kindle’s conversion mangles.
Size matters
There’s a hard 50 MB file size limit across all Send to Kindle methods. A typical EPUB novel is well under that, but illustrated books, comics, or PDF-heavy documents can hit the wall easily. For anything over 50 MB, USB transfer is your only option.
Quick summary
| Method | Best for |
|---|---|
| Web (amazon.com/sendtokindle) | Quick one-offs, no setup |
| Desktop app | Batch transfers |
| Sharing from anywhere | |
| Chrome extension | Web articles |
| Phone share sheet | Documents received on mobile |
| USB (drag to /documents/) | Files over 50 MB, preserving exact formatting |
Troubleshooting Send to Kindle Failures
File never arrives on the Kindle. The most common reasons: the Kindle is in airplane mode, the file exceeded 50 MB, the sender email address is not on the approved list, or the file format is not supported. Check Wi-Fi connectivity, file size, and the approved sender list before retrying.
EPUB formatting breaks after conversion. Amazon’s server-side conversion is aggressive. It strips embedded fonts, simplifies CSS, and sometimes reflows complex layouts. If a formatted file matters — for technical books, cookbooks, or anything with tables — sideload via USB instead. Drag the original file into the /documents/ folder to preserve formatting exactly.
The Send-to-Kindle option is grayed out on iOS. This usually means no Kindle apps are signed in. Open the Kindle app, confirm a login, then try sharing again. The share target only appears when the app is active.
Cover art does not show up. Amazon’s conversion sometimes discards cover metadata from sideloaded EPUBs. To fix, use Calibre to set the cover before sending. Right-click the book → Edit metadata → download or add a cover → then send via USB or email. Covers set in Calibre metadata survive Amazon’s conversion.
USB Sideloading: When You Need Exact Control
Send to Kindle is convenient but does not preserve formatting perfectly. For books where layout matters, USB transfer is the answer:
- Connect the Kindle to a computer via USB
- Open the Kindle drive (it mounts like a flash drive)
- Copy files to the
/documents/folder - Eject safely, then the books appear in the Kindle library
This method bypasses Amazon’s conversion entirely. No formatting changes, no file size limit, no delivery delays. Use it for manga (via Kindle Comic Converter), technical PDFs, and EPUBs with complex formatting where Send to Kindle would mangle the result.
The trade-off: books transferred by USB do not sync across devices. Reading progress, highlights, and notes stay on that specific Kindle. For Whispersync between a Kindle and phone, you must use Send to Kindle or buy from the Kindle Store.
Frequently Asked Questions
Can I send PDFs via Send to Kindle?
Yes, with limitations. PDFs under 50 MB work through all Send to Kindle methods. But PDF is a fixed-layout format — the text does not reflow. On a 6-inch Kindle screen, this means small text and constant zooming. Amazon does not convert PDFs to reflowable text during delivery. For PDF reading, consider a larger device or use k2pdfopt to reformat before sending.
Can I send books from Calibre directly to Kindle?
Yes. With the Kindle plugged in via USB, Calibre recognizes it as a device. Select books, click “Send to Device,” and Calibre converts and transfers them. For wireless transfer, use Calibre’s built-in content server — the Kindle browser can access it, but the experience is clunky. USB is faster and more reliable.
Why does Send to Kindle add my document to the cloud but not my device?
Send to Kindle delivers to Amazon’s cloud first, then pushes to devices. If it appears in “Your Content and Devices” on Amazon’s website but not on the Kindle, the Kindle is likely offline. Connect Wi-Fi, then sync manually by swiping down and tapping the sync icon. Documents stuck in the cloud for more than a few minutes usually mean the Kindle cannot reach Amazon’s servers.
Can I send Kindle books to a friend’s device?
No. Send to Kindle is tied to a Amazon account. Books sent via this service go to your library, not someone else’s device. To share a DRM-free book, send the file file (USB or email attachment) and let them use their own Send to Kindle. To share a Kindle Store purchase, use Amazon’s Family Library feature instead.