Thursday, October 12, 2017

Understanding Read-Through and Why It Matters

By Marcy Kennedy, @MarcyKennedy

Part of the Indie Author Series

A couple of months ago, I started a series on advertising as an indie author. We’ve already looked at a big picture overview of when and what we might want to advertise, and we talked about whether there’s ever a time when it’s okay to lose money on advertising.

Last month, I started talking about making sure we know whether we’re earning or losing money on our ads. This month, I’ll be continuing on to look at how read-through affects our return on investment.

(If you’re writing only standalone books that aren’t part of a series, you might still be able to get something from this post, but it’s mainly geared to series books. Sorry!)

Read-through is whether our readers continue on to the next book in the series. It comes in two “types”—book-to-book read-through and series cumulative read-through. Cumulative read-through is more important for ROI on ads, but book-to-book read-through is still something we should look at for overall career health.

Book-to-Book Read-Through

As indie authors, one of the things we need to do to grow our career is identify when things are going wrong and why they went wrong. Book-to-book read-through can’t give us the why, but it can tell us the where. It can show us if we’re losing readers at a particular spot within our series. It can also show us if a series is thriving or dying. If we’re writing a dying series, it might be time to move on to something new.

Calculating read-through requires a simple formula: (Book 2 Sales/Book 1 Sales) x 100 = book-to-book read-through rate.

Remember, you need to take the numbers for the same period of time for each book, and you want to pick a big enough sample. I recommend not looking at anything smaller than a month of sales.

For example, let’s say that over the course of a month, Book 1 sold 81 copies and Book 2 sold 70 copies. Our formula would look like this…

(70/81) x 100 = 86% read-through

To continue on, we’d simply slot the next books in the series into the formula so that it looked like (Book 3 Sales/Book 2 Sales) x 100.

If at any point we see a read-through between books of less than 50% that’s a major red flag.

If we see steadily decreasing read-through as the series progresses, that’s also a warning sign. Generally, once readers get into a series, they’ll continue on unless something is very wrong. If you notice your read-through rate going down, there’s a problem.

Here’s an example of what a book-to-book read-through rate might look like for a healthy series:

Book 1 to Book 2 – 70%
Book 2 to Book 3 –90%
Book 3 to Book 4 – 91%

Here’s what you don’t want to see:

Book 1 to Book 2 – 70%
Book 2 to Book 3 – 60%
Book 3 to Book 4 – 55%

If we’re in Kindle Unlimited, we can do a similar calculation for page reads. Because Kindle Unlimited readers tend to be voracious and are borrowing rather than buying, we’d be looking to see a higher read-through rate as a sign of a healthy series.

Series Cumulative Read-Through

For series cumulative read-through, we’re looking at how many people who start the series finish it. To figure it out, we can use the formula (last book sales/first book sales) x 100.

For example…

(55/81) x 100 = 68%

Approximately 68% of the people who begin our series will read all the way through.

That’s good to know, but in terms of ads, what we really want to know is what a sale of each Book 1 is really worth to us.

If you want the fast and easy way to handle this, I recommend simply downloading Michael Cooper’s Book Read Through Calculator. You can put in your numbers, and it’ll handle the calculations for you.

If you want to do this manually, you’ll compare the sales of each book in the series to the first book.

(Book ? Sales/Book 1 Sales)

Let’s say we had a four-book series and the numbers look like this…

Book 2 = (70/81) = 0.86
Book 3 = (65/81) = 0.80
Book 4 = (60/81) = 0.74

We’ll then need to multiple those numbers by the net profit we make on each of those books. (If you don’t remember how to figure out the net profit, I explained it in my post Are Your Book’s Ads Earning or Losing You Money?)

Let’s say that we’re selling Book 1 for $0.99 and the other three books in the series for $2.99 each.

Book 1 = $0.29
Book 2 = $2.03 x 0.86 = $1.75
Book 3 = $2.03 x 0.80 = $1.62
Book 4 = $2.03 x 0.74 = $1.50

Add up all the final numbers and we get $5.16. For every copy of Book 1 that we sell, we’re earning $5.16 overall thanks to readers continuing on through our series.

How Does This Affect ROI?

If you remember from the last post, in our fictional example, we said our ad sold 15 copies more than we’d have sold normally. This earned us a total profit of $4.35 from the sales of Book 1 alone. We paid $16 for the ad.

ROI = (4.35 / 16) x 100 = 27%

If we’re taking into account our read-through, it changes dramatically.

15 copies sold x $5.16 = $77.40

ROI = (77.40 / 16) x 100 = 483%

The ad that originally looked like it lost us money actually yields us an excellent return on investment when we consider people reading through our series.

Do you have any other helpful tools you’d like to recommend for tracking sales or read-through rates? Please share them in the comments!

Marcy Kennedy is a mystery and speculative fiction writer who believes fantasy is more real than you think. Alongside her own writing, Marcy works as a freelance fiction editor and teaches classes on craft and social media. She’s also the author of the Busy Writer’s Guides series of books. You can find her blogging about writing and about the place where real life meets science fiction, fantasy, and myth at

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  1. Hello. My question has to do with writing series but not publishing in order. The reason being is that although the first book really doesn't have anything to do with the main character except in foreshadowing the concept of her. Yet, the second, third, and fourth, do.
    HOWEVER, when I started writing the series, books 3 and 4 have merged with 5, which is the actual START of not only her adventure of (trying)to end her torment, but also those who were responsible (in part, but unknowingly) for it. It IS the book that started it all but has morphed into this huge monster of an Origin story. It doesn't even touch in "real time" until the 5th book.
    So, my question is: How does one handle such an epic story without spending more years that I already have (13) on it? Every time I try to go back to book 5, more questions emerge that send me back to those first 4 to find answers. I'm not really that concerned with 3 and 4 because they work themselves out more or less within 5, but those first two keep haunting me.
    I apologize if this sounds confusing or a mess but it really has me at my wits end. Thirteen years of research, writings, puzzle pieces, piles of post-its, sketchbooks of concept art, tons of "how to"'s all getting me a bit bummed that I have yet anything to show for it except, possibly, my determination not to give up.
    If there is any advice or options that anyone could throw my way, I would be forever grateful.


  2. Anyone? Or, is it just a mess?

    1. Sorry Stephanie, I think Marcy missed this one :)

      It's hard to say without knowing more, but it sounds to me like you have a lot of backstory and origin tales, but the actual story starts in book 5. If that's the case, then you wouldn't need the first 4 books. Or those books are part of another series that series leads into a new series starting with book 5 (does that make sense?)

      If books 1-4 are all setup and don't have a protagonist solving a problem all on their own, then they're aren't part of the book 5 story. If that's where the story starts, then that's book 1 of that series.

      But if your protagonist is driving the story in books 2-5, and 5 is just the start of the final act or climax of her story, then your series probably starts at book 2 and book 1 is just setup. It could work as a separate prequel tale if it stands alone without the other books.

      I'd need to know more about the series to offer more help, so if you want to email me we can discuss it more there.

  3. Thank you so much, Janice! I will do that soon! I just got home from work (12am) and I will need to get my stuff in order so my email isn't all over the place ;-).

  4. I have a series out that stands at 9 books and counting. I notice a significant drop off between books 2 and 3 and then from 3 to 4 but, after that, the read through is above 90%. The flip side of this is, The first book in the series is free everywhere. The second is very low priced. That contributes to some of the drop off but not all of it. People aren't actually abandoning the series after books two and three. To the contrary, they seem to be embracing it.

    I have a boxed set of the first 8 books at the biggest retailer that does quite well and 2 four book sets at all the other retailers that do well. Many readers pick up the freebie and the cheap book and then go on to buy the bulk of the series at a huge discount over buying individual books. Series authors with boxed sets need to account for the sales of those sets when considering read through/sell through rates.

  5. I finally got around to emailing you back, Janice. :)

  6. Janice—do you have any statistics on read thru for non-series? What read through rate can I reasonably expect for my three standalone books?

    1. I don't have those, as Marcy Kennedy wrote this article. I Googled it, but didn't find anything on standard numbers, and nothing on stand alone novels. I'm not sure there is an average rate though.

      I'd imagine that the numbers are similar to a series. If someone likes your books, odds are they'll buy your next one unless it's vastly different. Such as a different genre.

    2. Just watched a webinar that gave some info on this. A way to get read through is to check reviews. Look at the number of reviews on book one. Then look at the reviews for the next books. Do the math to find the ratio and percentage. For example, if you see 100 reviews for book one, and 40 reviews for book two, that's a 40% read through.