Book preflight, explained simply
What is book preflight?
You wrote the book. Before Amazon KDP or IngramSpark will print it, a machine checks your two files: the cover and the inside pages. Preflight is you checking them first, so nothing gets sent back.
Book preflight is checking a book's cover and interior PDF files against the printer's rules (size, bleed, margins, colors, picture sharpness, fonts and spine width) before uploading, so the printer accepts them the first time.
Why printers send files back
A printed book is not a big printout of your Word file. The printer prints your cover on a larger sheet, trims it, folds it around a spine that is exactly as thick as your pages, and glues it on. The inside pages are printed with ink, not light, and are bound so part of every page disappears into the fold.
Each of those steps has a rule. If your file breaks one, the printer either rejects it or prints something you won't like: a white line on the edge, words cut off near the spine, a muddy photo or a title sliding off the side of the spine.
The six things every preflight checks
How preflight fits into publishing
- Finish your files. A cover PDF and an interior PDF, made at your book's trim size (for example 6" x 9").
- Preflight them. Check every rule above, for your printer, for this exact page count and paper.
- Fix what failed. Then check again. A fix to one thing (like the page count) can break another (like the spine width).
- Upload. The printer runs its own check. If you preflighted well, this is where your book is accepted.
- Order a proof copy. Hold the real book in your hands before you hit publish.
Preflight doesn't replace the proof copy. It makes sure you get to the proof copy without a rejection email first. See preflight vs. a proof copy for the difference.
Who needs it
Anyone sending a print book to Amazon KDP, IngramSpark, Barnes & Noble Press or Lulu. First-time authors need it most, because nobody tells you these rules until a file comes back. Seasoned authors need it when they switch printers, change paper, add pages or go from paperback to hardcover. Here's who needs what.
Three ways to preflight
| Way | Cost | Time | Catch |
|---|---|---|---|
| Check it yourself with a checklist | Free | An evening or two | You need Adobe Acrobat Pro for some checks, and you have to know what you're looking at. Use our checklist. |
| Pay a designer or formatter | Reedsy's pros: median ~$930 for a cover, ~$800 average for formatting | Days to weeks | Not every freelancer checks your printer's exact rules. A pretty file can still be rejected. |
| Use a preflight tool like SparkPrep | Free scan, $1.99 audit | Minutes | You upload your PDF. SparkPrep checks it against your printer's own numbers and can fix what it finds. |
For the full story on costs and timing, read what it really costs to get a print book ready.
Find out what's wrong with your files before the printer does
SparkPrep checks your cover and every interior page against the exact rules Amazon KDP, IngramSpark, Barnes & Noble Press and Lulu use, tells you each problem in plain English, and can fix it for you.
Scan my book free See how SparkPrep worksThe scan is free and shows how many problems your files have. To see every problem and where it is, the audit is $1.99 ($3.99 after January 1). The Advanced Audit checks every page, up to 300, for $9.99.
Questions people ask
What does preflight mean in self-publishing?
It means checking your cover and interior files against the printer's technical rules before you upload them, so KDP, IngramSpark, Barnes & Noble Press or Lulu accepts them the first time.
Does Amazon KDP check my files for me?
KDP checks them when you upload and shows problems in its previewer. Preflight means you find and fix those problems before that point, and catch things the previewer only warns about.
Is preflight the same as proofreading?
No. Proofreading checks your words. Preflight checks your files: size, bleed, margins, colors, pictures and fonts.
How long does preflight take?
By hand with a checklist, an evening or two. With SparkPrep, a few minutes for the scan.
Free help from SparkPrep
Last updated 2026-11-01. Written by Joshua Davis, founder of SparkPrep. Numbers come from each printer's own published guides; always double-check your printer's current rules before you upload.