These classroom library labels are based off of Fountas and Pinell. I grouped the bin letters by grade level and also provided single letter labels as well.
In my classroom I attach these labels to bins and then also label my books by this system. There are many book leveling programs online, so it shouldn't be hard to find the levels of your books if you haven't already.
I also have Accelerated Reader labels created and will be adding others to the store soon!
There is also a page that allows students to write their reading goal and book level. Students then know what area of my bookshelf to checkout from. This provides a more meaningful reading experience for all of my children.