Amazon Best Sellers Rank
Amazon Best Sellers Rank explained in plain English for self-publishing authors, updated for 2026 KDP and publishing rules.
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Publishing glossary
Publishing terms, explained without the jargon
Self-publishing comes with its own vocabulary, and most of it is explained badly. Each entry here defines one term, says why it matters for your book, and stops before it turns into a lecture.
All glossary entries
Every term we have written up so far. More get added as authors ask about them.
ASIN
What an Amazon Standard Identification Number is, where to find yours, and how it relates to ISBNs when you publish on KDP.
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BISAC Codes
What a BISAC subject code is, how the nine characters break down, and why KDP asks you for browse categories instead.
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EPUB Format
What an EPUB file actually is, how it differs from PDF and MOBI, and which stores expect one when you upload.
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ISBN vs ASIN
The difference between an ISBN and an Amazon ASIN, when you need to buy one, and when the store hands you an identifier for free.
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Kindle Create
Amazon's free desktop formatting app: what it does, what a KPF file is, and when you can skip it entirely.
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MOBI Format
What a MOBI file is, why Amazon retired it, how it relates to AZW3 and KF8, and what to upload to KDP instead.
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Book Trim Size
Book trim size explained: what KDP supports, how 5x8 vs 6x9 changes your page count, spine and printing cost, and when you need bleed.
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