Density of whole milk according to first google answer is 1,034g/cm^3.
It's been a while, but would that make it 438,68 ml?
Edit: But I totally agree with your statement. SI/ metric units is superior in every way with how easy it is to convert between them.
At university in Norway I had American textbooks in all but one of my chemistry classes and all used SI/metric and proper names for the elements
The US isn't as entirely devoid of metric as a lot of people get the impression. We all learn it in school and are perfectly familiar with it, we just never made the switch for everyday units, so a lot of people lack the intuition around what the values mean. I can't tell you what 25c feels like without thinking about it for a minute.
I'm curious though, does anyone not use the proper names for the elements?