Choosing the right size garbage bag shouldn't require a Masters Degree
We're here to help.
First, determine the width of your container by measuring across the widest part and the height by measuring from bottom-to-top. Alternatively most manufacturers will have this information readily available.
Add 1-4 inches to the height for overhang - this will make handling and disposal much easier.
Voila - if you're having trouble getting an exact match do not stress an inch or two in either direction.