2026-11-09 · all guides
White Line on the Edge of Your Printed KDP Book? How to Tell a File Problem From a Trim Problem
TL;DR
A white line at the edge of a printed KDP page means the art did not extend far enough past the trim line. If the line shows up in the same place on every copy, including a proof and a purchased copy, the file is the cause. Check that the PDF page is your trim size plus 0.125 inch in width and 0.25 inch in height, then zoom in on the page edge. If you can see white between the art and the edge of the page, stretch the art to fill the whole page, upload again, and order one proof before buying more copies.
What you are looking at
KDP prints each page on a sheet that is slightly larger than the finished book, then cuts the top, bottom and outside edge. The cut removes 0.125 inch from each of those three sides.
If your picture or background color stops exactly where the page is supposed to end, the smallest shift in the cut leaves a strip of bare paper. That strip is the white line. Bleed exists to prevent it: the art continues 0.125 inch past the trim line, so the blade always lands inside ink.
The online previewer can't show this. It draws your page at its exact trim size, and the physical cut is never that exact.
First question: is it on every copy?
This tells you where to look.
| What you see | Most likely cause |
|---|---|
| The same line, same edge, on every copy, including a proof and a copy bought from the store | The file. The art stops short of the page edge. |
| One copy has the line and another copy of the same file doesn't | Normal cut variation, landing on a file with too little bleed to absorb it |
| The line is on the cover, next to the spine | The spine width or the cover background, not the interior |
In the first two cases the fix is the same: give the cutter more art to land in. The difference is only how sure you can be before you start changing things. If two copies from different print runs show the same line, don't order a third to see if it goes away.
The 30-second PDF check
Open the exact PDF you uploaded.
1. Check the page size. In Acrobat or Preview, look at the document properties. A book with bleed must be your trim size plus 0.125 inch in width and plus 0.25 inch in height.
| Trim size | PDF page size with bleed |
|---|---|
| 6 x 9 in | 6.125 x 9.25 in |
| 8.5 x 8.5 in | 8.625 x 8.75 in |
| 8.5 x 11 in | 8.625 x 11.25 in |
If the PDF is the plain trim size, the book has no bleed at all, even if the pictures touch the edge.
2. Zoom in on the edge. Go to a page with the white line and zoom to 400 percent or more at that edge. If you can see a hairline of white between the art and the edge of the page, you have found it. The page was made bigger, but the art wasn't.
3. Check the setting in KDP. On the paperback Content page, the interior must be set to Bleed. The file and the setting have to agree.
The free KDP margin calculator gives the exact PDF page size for your trim size with bleed on, plus the margins your text needs.
Why the art stops short
These are the usual reasons, most common first.
- The page was resized but the pictures weren't. Changing a Canva design or a Word page from 8.5 x 11 to 8.625 x 11.25 enlarges the page and leaves every image where it was. Each one has to be dragged out to the new edge.
- Pictures in Word are set "In Line with Text". An inline picture can't pass the margins. Set the wrapping to Behind Text, then stretch the picture to the page edge.
- The image has its own white border. Scans and some generated images come with a thin pale frame. Crop it off before placing the image.
- The PDF export shrank the page. A "fit to page" or "scale to fit" option adds a border around everything. Export at 100 percent.
- Bleed was added on four sides. KDP wants bleed on the top, bottom and outside edge only. On the inside edge, the art simply runs to the edge of the page. Our post on Canva and the insufficient bleed message covers this one.
Keep the important parts away from the edge
The outer 0.125 inch gets cut off, so nothing that matters can sit there. With bleed on, KDP's minimum outside margin is 0.375 inch, measured from the edge of the PDF page. Faces, page numbers and captions belong inside that margin. Backgrounds and scenery go all the way out.
If the line is on the cover
Covers always need bleed, 0.125 inch on every outside edge. A white line beside the spine is a different problem: the spine in the file is narrower or wider than the real one, so the fold lands on the wrong part of the art. Recalculate the spine for your final page count with the spine width calculator, and let the background color continue across the spine and a little onto both covers, so a small shift doesn't show.
Before you order more copies
Upload the fixed file, wait for it to go live, and order one proof. Check the same edge on the same pages. Buy the larger batch only after that copy is clean. If the books are gifts or stock for an event, allow time for this extra round.
If you would rather not rebuild the pages yourself, this is a job we do. Send the files through the manuscript formatting page and say where the line appears.
FAQ
Why did the KDP previewer look fine when the printed book has a white line?
The previewer shows each page at its exact trim size. The real cut can land slightly to either side of that line. Bleed is the extra art that covers the difference, and the previewer doesn't simulate the shift.
Are purchased copies checked more carefully than proofs?
No. Proofs, author copies and customer orders come off the same print-on-demand process, and nobody inspects the edges before a copy ships. If a proof and a purchased copy both show the line, the file is the cause.
Do I need bleed if only one page has art to the edge?
Yes. KDP's rule is that if even one page needs bleed, the whole interior file must be set up with bleed.
Will KDP reject a file with too little bleed?
Not always. A file can pass the upload checks and still print with a white edge, because the checks look at the page size and the margins. They can't tell that an image stops a hair short of the edge.
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