Will my PDF fit?
Drop a PDF to check it against Send to Kindle and reMarkable’s size limits. It runs in your browser, and nothing is uploaded.
The limits it checks
| Route | Largest file |
|---|---|
| Send to Kindle website | 200 MB |
| Send to Kindle by emailAll attachments in one email count together. | 50 MB |
| reMarkable web app or USBreMarkable points to its mobile and desktop apps for larger files. | 100 MB |
Figures from Amazon’s and reMarkable’s own pages, checked 2 November 2026. Amazon’s Send to Kindle app pages state no limit, so the app is not in the table.
How the check works
- The size comes straight from your disk. Your browser reports how many bytes the file has, without reading it anywhere else. We count 1 MB as 1,000,000 bytes, which gives the larger number and the safer comparison.
- The pages are counted in this tab. The page loads pdf.js, Mozilla’s open-source PDF reader, to count them. Your file is not sent anywhere.
- Each route gets a yes or no. You see how much room is left, or how far over the file is.
Over a limit? For a scanned book, the size is almost all page images. Clean black-and-white pages are far smaller than grey or colour ones, and the letters stay sharp. First check whether your file is a scan at all with is my PDF scanned?, then see why Send to Kindle fails on some PDFs.
Questions
What is the Send to Kindle file size limit?
Amazon’s Send to Kindle page takes files up to 200 MB on its website. By email, the limit is 50 MB in total per email, with up to 25 attachments. Amazon’s app pages state no figure.
What is the reMarkable file size limit?
reMarkable’s help article gives 100 MB for the web app at my.remarkable.com and for USB transfer. It sends larger files to the mobile and desktop apps and states no maximum for them.
Does Kobo have a PDF size limit?
Kobo’s file formats page lists PDF for its eReaders and Kobo Desktop and states no size limit, so this check leaves Kobo out.
Why is my scanned PDF so big?
Every page of a scan is a photo. In colour or greyscale, at a resolution fine enough for print, a few hundred pages add up fast, even though the text itself would take almost no space.
How do I make a PDF small enough for my Kindle?
For a scanned book, turning text pages into clean black and white shrinks it without blurring the letters. Our guide to a PDF too big for Kindle goes through the options.
My computer shows a different size. Which is right?
Both. Windows counts 1 MB as 1,048,576 bytes; macOS and this check count 1,000,000. The bigger number is the safe one to compare with a limit.
Is my file uploaded?
No. The size is read from your disk, and the pages are counted in this tab with pdf.js, Mozilla’s open-source PDF reader. Nothing is sent to us.