Every filter has two different sizes: nominal and actual.
The nominal size is the size printed on the filter. This size is normally rounded up, and the variance can vary by manufacturer.
The actual size is the size of the filter when measured.
The sizes listed on our size are the nominal sizes. The best way to tell your size if to look at your current filter. If you need help, we are standing by to assist you.
Have a non-standard filter size? We can make any 1" or 2" filter size from 4"x4" up to 30"x36", in 1/8" increments. Simply select your measurements on the drop down menus during signup. Need a hand? Simply fill out a help request below, or give us a call at 1-800-308-1186.