It's important that self-published writers keep an accurate total of their book sales. One aspect of this is the number of books sold and the money made. I've created a Google spreadsheet for just that. This is a public document, so feel free to copy it for your own use. Using this document, you enter the following each month: Total Income Total Sales As you enter these, you will automatically see the statistics for the following: Yearly Income Yearly Sales Per Month Income Per Month Sales Per Sale Income You can access this file here: Book Sales Statistics Spreadsheet Currently, I have spaces in there for sales during 2012 and 2013. I kept these on the same page of the document for quick and easy comparison. If you have any suggestions for improving this form, let me know in the comments.