Read-through is the number that tells you whether your series is working. It's the share of readers who finish book one and go on to buy (or borrow) book two, then three, then four.
It sounds like a spreadsheet thing. It is a little bit a spreadsheet thing. But it's also the number behind every smart decision you'll make about pricing and ads, so it's worth ten minutes.
Why it matters
When you sell book one of a series, you’re starting a chain. If half of your book-one readers go on to book two, every new reader is worth more than one book's royalty, and that changes everything:
- how low you can afford to price book one
- how much you can spend on ads to find a new reader
- whether the series is worth writing more books for
The basic formula
Read-through from one book to the next is simple:
So if book one sold 200 copies in a month and book two sold 110, your book 1 → 2 read-through is 110 ÷ 200 = 55%.
You can also measure the whole series at once. Take sales of the last book and divide by sales of book one. That tells you what share of readers make it all the way through.
A worked example
These numbers are made up, just to show the math:
| Book | Sales this month | Read-through from the book before |
|---|---|---|
| Book 1 | 200 | — |
| Book 2 | 110 | 110 ÷ 200 = 55% |
| Book 3 | 90 | 90 ÷ 110 = 82% |
| Book 4 | 80 | 80 ÷ 90 = 89% |
Notice the pattern: the biggest drop is almost always from book one to book two. Readers who make it to book two are hooked, so later books hold on to more of them.
How to count Kindle Unlimited reads
If your books are in Kindle Unlimited, a lot of your readers borrow instead of buy, and KDP reports pages read instead of copies. To turn pages into “full reads”:
The page count to use is your book’s KENPC (Kindle Edition Normalized Page Count), which KDP shows for books enrolled in KDP Select. It’s Amazon’s own page count, not your print page count.
So if book two had 33,000 pages read in a month and its KENPC is 300, that’s about 110 full reads. Add those to your sales for each book, then run the same formula.
What a good number looks like
There’s no single “right” read-through, but there are useful benchmarks. Book 1 → 2 read-through of around 50–60% is typical for paid sales, and 75% or more for Kindle Unlimited books that have found their audience (Kindlepreneur). In strong series, book 1 → 2 often lands at 40–60%, then drops by about 10–15 points for each later book (ScribeCount).
Use these as a rough guide, not a grade. Your own numbers, tracked over time, matter more.
What skews your numbers
Read-through can look wrong for reasons that have nothing to do with your story:
- A sale or free promo on book one. Bargain hunters grab book one but many never read it, so book 1 → 2 drops. Measure promo months separately.
- Timing. Readers take time to finish a book. If book one had a big week, book two’s sales may show up the following month. Look at longer windows, like 60 or 90 days.
- A brand-new release. If book three only just came out, its readers haven’t caught up yet.
- Box sets. Sales of a box set include several books at once, so count them separately.
- Different prices. A $0.99 book one and a $4.99 book two will behave differently than four books at the same price.
What to do with it
Work out what a new reader is worth
Add up the royalty from each book, weighted by how many readers reach it. Using the example above, with every book earning about $3.49 a sale:
- Book 1: $3.49 × 100% = $3.49
- Book 2: $3.49 × 55% = $1.92
- Book 3: $3.49 × 45% = $1.57
- Book 4: $3.49 × 40% = $1.40
That's about $8.38 per reader who starts book one, roughly two and a half times what book one alone earns. (The percentages here are each book's sales compared with book one: 110, 90 and 80 out of 200.)
Decide whether ads pay
If a new reader is worth about $8.38 across the series, you can afford to spend up to that to get someone to buy book one and still break even. Spend less and you're profitable. Spend more and you're paying for the privilege.
Decide how to price book one
Strong read-through means you can price book one low, even at $0.99, because you make the money back on books two, three and four. Weak read-through means a cheap book one just loses money. Fix the read-through first.
How to improve it
- Put a link to the next book right after “The End.” Not after the acknowledgments. Right after the last line.
- End with a pull. Close this couple’s story completely, but leave a door open: a side character’s trouble, a new threat, a teaser chapter.
- Make the series obvious. Matching covers, series name and number on every book, and a series page on Amazon.
- Release on a steady rhythm. Long gaps let readers forget you.
- Check book two’s blurb and opening. If readers buy book two and stall, the problem may be its first chapters, not book one.
Go deeper
Chapter 1 of Plot. Publish. Profit. explains why series are the engine of a catalog, and chapter 15 shows how to design your series for read-through from day one. See also: series vs. standalone.
