[geocar]

I was taught to bake (and write recipes) using a mixture of units; to prefer metric measurements when precision is required, but to prefer "American" units when it isn't, almost to highlight the absence of precision, and to clue the reader that they may have to adjust for humidity or the amount of gluten generated (or whatever).

I know this stuff is obvious to an experienced cook, but I can also imagine seeing 14,2g of anything causing some unnecessary distress when trying to work with an unfamiliar recipe.

Maybe something like "1c of flour (approx. 120g)" is a good way to be safe?

If you're looking for an engine for actually doing the conversions, there's GNU units[1] and Frink[2] which both contain databases of these conversions you may be able to mine.

[1]: https://www.gnu.org/software/units/

[2]: https://frinklang.org/

[Symbiote]

I have friends who sometimes help me cook a dinner for more friends. I've seen some of them try to measure out 22.5mL¹ of olive oil for frying because I pressed a button on the site to 1.5× the recipe...

Recipe websites don't include that first 10 pages of a "beginner" recipe book, which usually describes how to measure ingredients and the various cooking techniques used.

¹ 1.5 metric tablespoons, 1.5 × 15mL.