Estimates "Books per day" based on the Amazon Sales Rank
First, you will need to get the bookmarklet loaded in your browser. Here's a handy snippet of HTML to help with that.
<a href="javascript:(function(){var jsCode = document.createElement('script');jsCode.setAttribute('src','https://cdn.rawgit.com/m3mnoch/sales-rank-estimator/master/bookmarklet-external.js');document.body.appendChild(jsCode);}());">This is the link.</a>
Or, if you'd just like to copy-paste the code into one of your existing bookmarks, you can use this:
javascript:(function(){var jsCode = document.createElement('script');jsCode.setAttribute('src','https://cdn.rawgit.com/m3mnoch/sales-rank-estimator/master/bookmarklet-external.js');document.body.appendChild(jsCode);}());
Second, browse to an Amazon book page and click your bookmarklet.
For example: http://www.amazon.com/gp/product/B00X6KZ6SW/
At the time of this writing gets:
Sales Rank: 1925
Units per day: 92
Price per Unit: $1.99
Sales per day at 15%: $27.46
Sales per day at 70%: $128.16
What's a bookmarklet, you ask? Here's a helpful link that, helpfully, might be helpful. https://support.mozilla.org/en-US/kb/bookmarklets-perform-common-web-page-tasks
Where did you get these calculations? i've dug up from one of those experts who study these sorts of things! this guy: http://kindlepreneur.com/amazon-kdp-sales-rank-calculator/
He has lots of other tools and such to check out. http://kindlepreneur.com