I'm old enough to remember computers being pitched as devices that can do tedious math for us. Now we have to do tedious math for them apparently.
I'm sure you would like to memorize all kinds of API instead of having something idiot proof and straightforward
Hey that's a great joke, you made me spill my morning home-brewed kombucha.
I'm going to steal that one for my JavaScript monthly developers meetup.
Is it ok if I attribute it to "Xirdus on Hacker News"?
Hence the way I would do it (and have for other purposes), as stated in my final sentence. Have the human state the intent and convert to your own internally preferred units as needed.