This one feels unfair: the document looks right on your screen. But KDP doesn't grade looks — it measures. Every page of your interior PDF must be exactly your selected trim size (or your trim size plus bleed, if your book uses bleed), and if the numbers don't match, the book comes back.
What KDP is actually saying
PDFs store page size in points: 72 points = 1 inch. So to read any PDF, divide its points by 72. The common sizes:
| Trim size | In points | With bleed, in points |
|---|---|---|
| 8.5 × 11″ | 612 × 792 pt | 621 × 810 pt |
| 8 × 10″ | 576 × 720 pt | 585 × 738 pt |
| 6 × 9″ | 432 × 648 pt | 441 × 666 pt |
| 5.5 × 8.5″ | 396 × 612 pt | 405 × 630 pt |
(Bleed adds 0.125″ — 9 points — to the width, and 0.25″ — 18 points — to the height. If your file is off from a round trim size by exactly 9 or 18 points, you're not looking at a wrong trim at all: you're looking at a bleed mismatch, which the bleed guide covers.)
The usual culprits:
- A4. Outside the US, most software defaults to A4 — 595 × 842 points. Close to US Letter, not equal to it, and KDP treats “close” as wrong.
- A converter or print dialog quietly scaled the file. “Fit to printable area” shrinks every page by a few percent. The document still looks perfect; the measurements are all off.
- The design tool and the bookshelf disagree. The doc was built at 8×10″ in Canva, the book was set up as 8.5×11″ on KDP — or the other way around.
- One odd page. A single landscape insert, one page exported from a different tool, one page at a different size — the whole file gets flagged, because every page must match.
Check it yourself
- Open the PDF in Acrobat or the free Acrobat Reader. File > Properties > Description shows the page size. (In Acrobat, hovering the bottom-left corner of the window also shows the size of the page you're on.)
- Check more than the first page — look at a middle page and the last page too, hunting for an odd one out.
- Compare against your bookshelf setup: the trim size you selected for this book, and whether you told KDP the book has bleed.
- Divide by 72 if your tool reports points, and compare with the table above.
Don't want to measure this yourself? Send us your interior and cover files and we'll run the full 13-point check — page size, bleed, margins, fonts, all of it — and tell you in plain English what's wrong. The check is free. Get the free check →
How to fix it
In Word
Layout > Size > More Paper Sizes, and type your exact trim size. Then export with Save As > PDF — never Print-to-PDF with “fit” or scaling enabled, because the print driver will shrink the page to your printer's printable area.
In Pages (Mac)
File > Page Setup > Paper Size > Manage Custom Sizes, and add your exact trim size (or trim plus bleed). Pages loves defaulting to US Letter or A4 depending on your region — set it explicitly, don't assume.
In Canva
Resize the design itself to the trim size in inches (Canva may ask in millimetres: 8.5×11″ is 215.9 × 279.4 mm; 6×9″ is 152.4 × 228.6 mm). Download as PDF Print, adding crop marks and bleed only if your book actually uses bleed.
In InDesign
File > Document Setup — set width and height to the trim, and the bleed separately. Export and then measure the exported PDF; the export preset, not the document, is where mismatches sneak in.
Whatever tool you use: export one chapter first, measure the test PDF, and only export the whole book once the numbers are right. Five minutes of testing beats a full-book rejection.
The honest limit
Don't “fix” this by stretching the PDF to the right page size. Scaling stretches everything — text grows or shrinks, margins deform — and the book comes back rejected again, this time for margins or type size. If the document was authored at the wrong size, set the correct size in the source and re-export. It's an annoying hour; it's also the only version of this fix that stays fixed.
Or send us the files — the check is free
Email your interior and cover PDFs and we'll tell you exactly what's wrong — in plain English, free, within 48 hours. If it does need fixing, the by-hand fix is $19 and we redo it free if KDP rejects it for a formatting issue we were hired to fix. We rebuild files to be compliant with KDP's published spec — that's the promise we can keep.