huf [he/him]

realistically, nobody uses all the units.

eg, decimeters are practically unheard of.

anyway, start measuring things around you. like your fingers, your hand, your ceiling height, that sort of thing. and then remember what those measurements feel/look like. that’ll give you something to compare other things to. you can do the same thing with volume measurements and so on.

for example, i found that one of the knuckles on one of my fingers is exactly 4cm long, so i always have that with me.

milk comes in 1L boxes, for example, so pretty much everyone knows what a liter is.

sugar and flour come in 1kg bags and that’s roughly 1 liter too