If you read the instructions on Createspace, or any of the POD sites, then you probably ended up just downloading a template and pulling a few hairs from your head while trying to get the template accepted. Calculating the book and/or spine width dimensions is actually pretty easy once you realize you only need to know a couple of things.
How to Calculate the Spine Width for Createspace
Determine the interior page count. Before you can begin figuring out what the spine width is you need to know what the final formatted interior page count will be because the spine width is calculated using the interior pdf page count. If the page count changes, then the spine width changes. This is why I usually advise people not to worry too much about the exterior until they fully get the interior prepared.
Once you’ve formatted the interior and know the final pdf page count, you’re ready to begin your calculations. It’s pretty simple. Just mulitply the page count by the paper width. At Createspace you have two papers to choose from– white or cream. Each has their own width. If you calculate using white but when you upload decide “hmm I think I like cream better” and choose cream then your exterior pdf could get rejected because the size for cream paper is not the same as the size of white paper.
Now once you’ve decided on what paper you prefer you’re ready to multiply. For this example, I’m going to use 5×8 trim size with 250 pages, but regardless of what trim or what the page count is, the same method applies.
The formula is:
page count multiplied by paper width.
White paper width is 0.002252
Cream paper width is 0.0025
So for a 250 page book with white paper your formula looks like this: 250 x 0.002252= 0.563
I usually round up so I only have two numbers after the decimal so my spine width would 0.56 if I used white paper.
For cream paper it would be 250 x 0.0025= 0.625 (or 0.63)
As you can see depending upon which paper you use alters the width of the spine which is why it’s important for you to give your cover designer the exact specifications you intend to use when you upload because if you change your mind last minute you might incur fees because the cover designer would have to alter the entire cover. Because changing the spine width changes the overall cover dimensions.