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Self-publishing guides

Short, sourced answers to the questions authors ask before they publish. Every number comes from the retailer's own help pages.

  • Updated

    How to format a KDP book description

    The 12 HTML tags KDP allows in a book description, the 4,000 character limit, what is not allowed, and before and after examples.

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    What is a good ACOS for books?

    A good ACOS is one below your break-even ACOS. Break-even by format and price for KDP paperbacks and ebooks, plus how KU reads and series read-through change it.

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    What size should a Kindle ebook cover be?

    KDP's ideal Kindle cover is 1,600 x 2,560 px. The minimum size, the 1.6:1 ratio, file types and file size, other stores' rules and the mistakes to avoid.

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    Do you need an ISBN for KDP?

    When KDP requires an ISBN, when it is optional, what the free KDP ISBN can and cannot do, and when to buy your own. Straight from KDP's help pages.

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    How much does KDP charge to print a paperback?

    KDP paperback printing cost explained: the fixed fee, the per-page rate, short book pricing, large trims and color, with worked examples and a table by page count.

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    KDP's new 70% royalty range: $2.99 to $12.99

    Since July 7, 2026, Kindle ebooks priced $2.99 to $12.99 on Amazon.com qualify for KDP's 70% royalty. What changed, the formula and what you earn at each price.

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