it's beyond me

it's beyond me

It is advanced beyond my ability to understand or make sense of the subject matter or task at hand. I can't follow any of the stuff they're teaching in this advanced math class. It is definitely beyond me. It is beyond me why you don't help with the chores even after I've asked you several times.
See also: beyond

it's beyond me

it's too astonishing, puzzling, etc. for me to understand or explain. informal
See also: beyond