Quick Answer: To format a KDP paperback interior, set the document to your trim size (6×9" is standard), turn on mirror margins, and set the inside (gutter) margin to KDP's minimum for your page count — 0.375" up to 150 pages, 0.5" for 151–300, 0.625" for 301–500, 0.75" for 501–700, 0.875" for 701–828 — with outside, top and bottom margins of at least 0.25". Use an 11–12pt serif body font, Roman-numeral front matter and Arabic main-text page numbers, keep images at 300 DPI, then export a PDF/X-1a file with every font embedded and the page size matching your trim exactly. Run a free KDP Readiness Score before you upload.
Full walkthrough, tools and UK costs below.
KDP paperback formatting is the process of preparing your manuscript's interior layout specifically for Amazon KDP's print-on-demand paperback service. This involves selecting a trim size (6 x 9 inches is the industry standard), setting margins that meet KDP's minimum requirements (the inside gutter margin ranges from 0.375 inches for books under 150 pages to 0.875 inches for books over 700 pages), formatting paragraph styles with a readable serif font at 11-12pt, inserting page numbers and running headers, adding front matter (title page, copyright page, table of contents) and back matter, ensuring all images are 300 DPI in CMYK colour space, and exporting as a PDF/X-1a file with embedded fonts. For UK authors, additional considerations include purchasing a Nielsen ISBN (£93 single, £174 for ten), understanding VAT at 0% on printed books, and pricing in GBP. This guide provides a complete walkthrough of the KDP paperback formatting process with exact specifications, common error fixes, and UK-specific requirements.
Last reviewed by Robert Prime — June 2026
We see this come through our formatting queue at publishing.co.uk regularly, so the patterns and fixes here are based on what actually works at upload.
Introduction
Formatting a paperback for Amazon's Kindle Direct Publishing (KDP) is often framed as a straightforward, plug-and-play process. Yet anyone who has ventured through the minefield knows the reality is far from it — particularly for UK authors navigating nuances that US-centric guides gloss over. I’m Robert Prime, a UK-based author and digital business veteran with 25+ years in eCommerce and publishing. When I was preparing my own book, Google. Panic. Repeat., writing was the easy bit. The formatting — margins, trim sizes, font embedding, and file conversions — was a marathon of confusion, costly errors, and frustration.
Before I built publishing.co.uk, my first attempt at hiring a freelance typesetter cost me an extra £200 and weeks of delay to fix. Do your due diligence: check portfolios and reviews, or use a trusted UK-focused service.
Tools and Resources for UK Authors
Word Processors
- Microsoft Word: The most accessible and flexible tool for UK authors. Allows custom page sizes, margin settings, and style management.
- Adobe InDesign: The professional gold standard for layout and design. Expensive and with a steep learning curve, but unparalleled control.
- Affinity Publisher: A cost-effective alternative to InDesign, popular amongst UK indie authors for its one-time purchase model and powerful tools.
Formatting Software and Services
- publishing.co.uk: An automated formatting service tailored for UK authors. Produces KDP-compliant PDFs aligned with UK sizing and ISBN requirements. Saves hours of frustration.
- Vellum: Highly praised in the US, but expensive and less UK market-tailored.
- Scrivener: Best for writing and organising manuscripts; limited for print-ready formatting.
ISBN and Barcode Providers
- Nielsen ISBN Agency (UK): The official UK source for ISBNs. Website: nielsenisbnstore.com.
- Barcode generators: Free online tools like OnlineLabels Barcode Generator create EAN-13 barcodes from your ISBN.
KDP Resources
- Amazon KDP Print Guidelines: Essential reading for formatting specs: KDP Print Guidelines.
- KDP Print Previewer: Use this tool to preview your uploaded interior and cover files before publishing.
Cost Breakdown: What UK Authors Should Expect
| Service/Item | Typical Cost (GBP) | Notes |
|---|---|---|
| Single ISBN (Nielsen) | £93 | Essential for UK publishing rights |
| Block of 10 ISBNs | £174 | Economical if you plan multiple titles |
| Professional Cover Design | £300 - £600 | UK agencies like Spiffing Publishing charge ~£450 |
| Professional Formatting Service | from £69 | publishing.co.uk offers transparent pricing and automation |
| Print Cost (KDP, B&W, 200pp) | ~£2.40 per copy | Varies by page count and trim size |
| Proof Copies | £3 - £5 per copy | Ordering physical proof highly recommended |
| Software (Word, Affinity, InDesign) | £0 (Word often included) to £50/month (InDesign subscription) | Affinity is one-off £55; InDesign is subscription-based |
Hidden costs to consider:
- Time spent troubleshooting formatting errors.
- Delays from ordering and receiving proof copies from the US.
- Potential costs from reformatting if you change trim sizes or page counts.
Frequently asked questions
Can I do this in Word or do I need specialist software?
Word can produce KDP-acceptable files but takes effort. Tools like Atticus, Vellum, or Reedsy Editor are faster for novels. For complex layouts (cookbooks, picture books) Adobe InDesign is the professional standard.
What's the minimum quality bar for KDP acceptance?
Embed all fonts, 300 DPI for any images, no bleed unless declared, trim size matched between cover and interior, single-page PDF for cover (not separate front/back). KDP accepts about 90% of files that meet these basics.
How long does the formatting process take?
DIY: 10-30 hours first time. Using a tool with templates: 2-6 hours. Paid service: 24-72 hours and no learning curve.
Should I order a proof copy before going live?
Yes — always. Proof copies are £4-£8 each and catch issues monitors don't show: paper bleed-through, spine alignment, cover gloss/matte feel.
About this guide
Written by Robert Prime for publishing.co.uk. Last reviewed June 2026. Specs and pricing change — verify current figures with the linked sources before relying on them.
