I have been looking for a carrying case for my adult coloring book, when I seen this and the description 12" x 10" I knew this case would work perfect..... No No No, those are the measurements for the outside. Once you open the case the measurements are 11" x 7" give or take little. My Adult Coloring Books measures 11" x 8". I would have giving this a five star rating but was very disappointed in the actual size. It is nice and sturdy and I believe would hold up well.