I spent a while this year writing a small zero-dependency library of health and fitness formulas — BMI, Mifflin-St Jeor, the US Navy body-fat equation, FFMI, Epley and Brzycki, Karvonen. Thirty-odd functions, no dependencies, ESM, one file. It should have been a boring job.
Source: [Dev.to](https://dev.to/javeed450sudo/a-formula-can-be-implemented-perfectly-and-still-give-the-wrong-answer-2d37)