Hong Life CalculatorsUnderstanding the eBook royalty calculator — concept and principle
Self-published authors are paid a royalty: a percentage of each eBook's price, often after a small per-copy delivery fee for the file download is taken off. This calculator estimates what you earn per copy and per month, so you can compare price points, royalty options and sales targets before you publish. It works with any currency; the example uses US dollars.
How it is calculated
- Earnings per copy = (list price − delivery fee per copy) × royalty % ÷ 100
- Monthly earnings = earnings per copy × copies sold per month
List price is the price you set, the royalty rate is the share the platform pays you, and the delivery fee is any per-copy charge for transmitting the file. As with Amazon KDP's 70% option, the fee is deducted from the price before the royalty rate is applied (enter 0 if your platform has none). Copies per month is your sales estimate.
The principle
A royalty is a revenue share: the platform keeps part of each sale to cover hosting, payment processing and its own margin, and pays you the rest. Because your earnings per copy are nearly a fixed share of price, total earnings scale in a straight line with both price and volume. In practice, price affects volume, so a lower price can earn more in total if it sells enough extra copies. The delivery fee matters most for large files such as illustrated books, where a fixed charge takes a bigger bite out of a low price.
Worked example
- Inputs: list price $9.99, royalty 70%, delivery fee $0.15, 200 copies per month.
- Price after delivery fee: 9.99 − 0.15 = $9.84.
- Earnings per copy: 9.84 × 0.70 = 6.888, shown as $6.89.
- Monthly earnings: 6.888 × 200 = $1,377.60.
How to read the result
Use the result to compare scenarios. For instance, test a lower price at a higher volume, or a lower royalty tier that allows a wider price range, and see which gives higher monthly earnings. Check each platform's own royalty rules carefully: some also deduct sales tax or VAT from the price first, and some charge no delivery fee at all; subtracting the fee after the royalty instead (9.99 × 0.70 − 0.15) would give $6.84 here, slightly less. Royalty rates, price bands and fees can also differ by country and by the store a customer buys from.
Common mistakes
- Entering a price that includes VAT when the platform calculates royalties on the price excluding tax.
- Ignoring delivery fees on image-heavy books.
- Assuming one royalty rate applies in every marketplace.
- Treating monthly earnings as income after tax; royalties are usually taxable.
Frequently asked questions
How many copies do I need to earn $1,000 a month?
Divide 1,000 by earnings per copy. At $6.888 per copy, 145.2, so 146 copies.
Is a 35% royalty ever better than 70%?
It can be if the higher tier requires a price range or delivery fee that does not suit your book. Compare both with the calculator.
Does the calculator handle print books?
No. Print royalties also subtract printing costs, which this formula does not include.
Sources: Kindle Direct Publishing Help, eBook Royalties (Amazon)