About Paperback Math

Free, fast tools that answer the fiddly numbers questions of self-publishing, so you can get back to the book.

Getting a paperback ready means a lot of small calculations: how wide the spine is, how big the cover file must be, what margins the printer needs, and what you'll actually earn per copy. Getting one wrong usually means a rejected upload or a wasted proof copy.

Paperback Math does that math for you. Every tool runs entirely in your browser. There's no account, and files you check are never uploaded. The specs come from each platform's published help pages, and we re-check them when platforms announce changes.

We started with Amazon KDP paperbacks, the most common starting point for self-published authors, and are adding other platforms and formats over time. Current tools:

• KDP Paperback Cover Size
• KDP Hardcover Cover Size
• KDP Spine Width
• KDP Cover Checker
• Lulu Paperback Cover Size
• Lulu Spine Width
• KDP Interior Margins
• KDP Royalties & Print Cost

Found a number that doesn't match your platform, or want a tool we don't have? Email [email protected].

Paperback Math is independent and not affiliated with or endorsed by Amazon, Kindle Direct Publishing or any other publishing platform.