Book Price Change Calculator
Before you change your book's price, see the royalty at both prices and how many copies a month you need at the new price to earn what you earn now.
How the calculator works
copies needed = (royalty now × copies now) ÷ royalty at new priceIt works out your royalty per copy at both prices with KDP's rules. For ebooks that is 70% of the price after VAT minus the delivery cost when the price is in the 70% range, and 35% outside it. For paperbacks it is 60% of the price at or above $9.99 (£7.99, €9.99) or 50% below, minus printing cost. Then it divides your current monthly income by the new royalty. The result is rounded up to whole copies.
Worked example: cutting an ebook price
A 1.5 MB ebook sells 60 copies a month on Amazon.com at $3.99, earning $2.63 each, $157.80 a month.
| New price | Royalty per copy | Copies needed | Sales change needed |
|---|---|---|---|
| $2.99 (70%) | $1.93 | 82 | +37% |
| $0.99 (35%) | $0.35 | 451 | +652% |
Going to $2.99 needs 37% more sales. Going to $0.99 needs 7.5 times the sales, which is why 99-cent prices only make sense for short promotions or a first-in-series book that sells the rest.
Worked example: a paperback just under the threshold
A 220-page 5.5" x 8.5" paperback on cream paper costs $3.64 to print. At $9.99 it earns $2.35; at $9.49 the rate drops to 50% and it earns $1.11. To match 30 copies a month at $9.99 you would need 64 copies at $9.49, 113% more, for a price only 50 cents lower. Readers rarely notice 50 cents; your royalty does.
Running a fair price test
Write down your copies per month for the four weeks before the change, then change one thing: the price. Leave ads, keywords and the cover alone for the test period. KDP says price changes can take up to 72 hours to show, so start counting from the day the new price shows on the store page. Compare the result with the "copies needed" figure: if you beat it, keep the new price; if not, change back.
Remember each marketplace has its own thresholds. If you price in US dollars and let KDP set other prices automatically, check the converted prices with the ebook royalty calculator or the paperback royalty calculator.
Frequently asked questions
How long should a price test run?
At least two weeks, and longer if you sell only a few copies a day. Daily sales swing a lot on their own, so a few days at a new price can mislead you. Avoid changing ads, the cover or the blurb during the test, or you won't know which change moved sales.
Why does a $2.99 to $2.98 change matter so much on ebooks?
KDP's 70% royalty only applies to ebooks priced from $2.99 to $12.99 on Amazon.com. One cent below or above that range drops you to 35%, so the copies you need roughly double. The calculator uses 70% whenever the price is inside the range for the chosen marketplace.
Do Kindle Unlimited reads change the answer?
KU page reads pay the same whatever your list price, so a price cut only affects the share of income that comes from sales. If half your income is page reads, a cut that needs 50% more sales to break even only needs to lift total income by about half that. Price drops can also lift your rank, which brings more borrows.
Is this the same as price elasticity?
It is the break-even side of it. The calculator tells you how much sales must change for income to stay the same. Whether they will is the test: run the new price and compare the actual copies sold per month against the figure here.
Sources
Rates last checked against KDP's help pages on 2026-10-16.
Guides that use this calculator
Related tools
- KDP Printing Cost CalculatorPrint cost per copy for every ink, trim and marketplace
- KDP Paperback Royalty CalculatorRoyalty per copy, minimum price and price for a target royalty
- KDP Hardcover Royalty CalculatorHardcover printing cost, royalty and minimum price
- Book Break-Even CalculatorCopies and months to earn back cover, editing and ad costs