Amazon KDP is one of the more transparent royalty platforms — the rate is published, the maths is simple, the rules are well-documented. But the rules have non-obvious gotchas: the 70% royalty isn’t universal, the file-size delivery fee surprises new authors, and paperback is a completely different model.
The calculator above handles all three: ebook 70% vs 35% maths, the $1.99-$9.99 sweet spot, paperback print-cost calculations.
The 70% / 35% decision
For ebooks, you choose either 70% or 35% royalty when you publish. The choice isn’t free — 70% has restrictions:
- List price $1.99-$9.99 in the US store (the US store has an equivalent range in dollars). Outside this range, you’re forced to 35%.
- Delivery fee charged at ~$0.10 per MB. Most plain-text books are 1MB; image-heavy books can be 10MB+. The fee comes off your 70% royalty.
- Distribution restrictions in some markets (mainly outside US/US/EU; Brazil/Mexico/India default to 35% unless you’re in KDP Select).
The numbers, for a 1MB ebook at typical prices:
| List price | 35% royalty | 70% royalty | Better |
|---|---|---|---|
| $0.99 | $0.35 | not eligible | 35% (forced) |
| $2.99 | $1.05 | $2.02 | 70% |
| $4.99 | $1.75 | $3.42 | 70% |
| $7.99 | $2.80 | $5.52 | 70% |
| $9.99 | $3.50 | $6.92 | 70% |
| $12.99 | $4.55 | not eligible | 35% (forced) |
The 70% rate is roughly 2x the 35% rate at the same price point. Pricing strategically inside the $1.99-$9.99 range is one of the biggest decisions a KDP author makes.
File size matters more than authors realise
The $0.10/MB delivery fee on 70% mode quietly punishes image-heavy books:
- 1MB book: $0.10 delivery fee, $3.42 royalty on $4.99 list (70%)
- 5MB book: $0.50 delivery fee, $3.14 royalty on $4.99 list (70%)
- 10MB book: $1.00 delivery fee, $2.79 royalty on $4.99 list (70%)
Cookbooks, photography books, illustrated children’s books, and design references can easily be 10-30MB if not optimized. Compress images, use efficient formats, and the savings are direct margin. A photography book optimized from 25MB to 5MB saves $2.00 of delivery fee per copy — at 1,000 copies that’s $2,000.
Paperback: a different game
Paperback uses a completely different model:
Royalty = list price - print cost - (list × 40% Amazon take)
Print cost = $0.85 + $0.012 × page count (B/W; color is more)
So a 200-page paperback at $9.99: - List: $9.99 - Print: $0.85 + $2.40 = $3.25 - Amazon take: $9.99 × 40% = $4.00 - Royalty: $9.99 - $3.25 - $4.00 = $2.74
The 40% Amazon cut + variable print cost means paperback economics are completely different from ebook. Three rules of thumb:
- Page count matters a lot. A 400-page paperback costs $5.65 to print — the breakeven is much higher.
- Lower-page books work at lower prices. A 100-page paperback at $6.99 royalties $2.34 (workable). A 100-page paperback at $9.99 royalties $3.94 (good).
- Don’t price paperback identical to ebook. Most successful KDP authors set paperback ~50-80% above ebook price.
KDP Select trade-off
KDP Select is Amazon’s exclusivity programme. Enrol your ebook for 90 days, can’t sell it on other ebook platforms, in exchange for:
- Kindle Unlimited inclusion — KU subscribers can borrow your book; you earn ~$0.005 per page read. For genre fiction with engaged readers, KU income often exceeds direct sales.
- 70% royalty in additional markets — Brazil, Mexico, India, Japan default to 35% outside Select; in Select they get 70%.
- Promotional tools — Free Days, Countdown Deals (time-limited price drops with maintained 70% royalty).
The cost is exclusivity. Apple Books, Kobo, Google Play, Barnes & Noble — all locked out. For some authors this loses 30-50% of revenue (audience reads on those platforms); for others it gains 30-50% from KU pages-read.
Genre fiction writers with active KU-reading audiences often win with Select. Niche non-fiction authors with reader bases on Apple Books or Kobo often lose. Run the maths after first publishing wide for 6 months, then making the call.
What this calculator doesn’t model
- KDP Select / Kindle Unlimited pages-read income — separate revenue stream not modelled
- Marketing costs — Amazon Ads, BookBub features, blog tour costs typically $200-$2,000 per launch
- Series economics — book 1 free / $0.99 + book 2-7 full price model
- US/EU market pricing — US only here
- Income tax — see side hustle tax calculator
Tax: it’s all self-employment income
KDP royalties are US self-employment income. Above $400 self-employment threshold: self-employment tax (Schedule SE) + federal/state income tax on net (royalties minus expenses like editing, cover design, marketing). For US-based authors, Amazon does not withhold income tax from royalty payments — you submit a W-9 to confirm US tax status, and paying estimated quarterly taxes plus self-employment tax on net royalty income is entirely your own responsibility (W-8BEN is the form non-US authors file, and only applies to foreign, not US, KDP accounts).
Many authors treat KDP as their primary income — for them, the earn-to-quit calculator shows the gross royalty volume needed to replace a day job. For most authors KDP is a side income; the side hustle tax calculator handles stacking on top of W-2 wages.
Hardcover — the third format most calculators ignore
KDP added hardcover as a third print format alongside ebook and paperback, using the same print-on-demand model as paperback but with a higher print cost and a different royalty formula: Amazon takes a 40% cut of list price, minus print cost, same structural approach as paperback but with hardcover's print cost running noticeably higher due to the case binding and jacket. Because hardcover print cost is higher, the list price has to be set correspondingly higher to preserve a comparable royalty — most authors price hardcover 40-60% above their paperback price for the same book. Hardcover tends to make the most sense for gift-market and collector-audience books (illustrated non-fiction, cookbooks, art books) where buyers are already primed to pay a premium for the physical object — pure genre fiction readers are far less likely to pay hardcover prices for a self-published title without an established author brand behind it.
Series economics — why book 1 pricing strategy differs from a standalone
The "book 1 free or $0.99, books 2+ full price" model is standard practice for KDP series, and the economics behind it are straightforward once modeled: a free or near-free first book isn't meant to earn royalty income directly — it's a customer acquisition cost, paid in foregone revenue rather than cash, to get a reader invested enough to buy the rest of the series at full royalty. This only works if the series genuinely delivers on that promise (a strong book 1 with a natural hook into book 2) and if there are enough books in the series to make the acquisition cost worthwhile — a 7-book series where book 1 is free but books 2-7 sell at $4.99/70% royalty recoups the "lost" book 1 royalty many times over per reader who continues; a 2-book series doing the same has a much thinner margin to work with. Authors publishing standalone titles don't have this lever available at all — for standalone books, the free/discount strategy has to work harder to justify itself, usually limited to short promotional windows (Free Days, Countdown Deals within KDP Select) rather than a permanent $0.99 price.