Building a BMI Calculator with Metric & Imperial Support in React
javascript
dev.to
BMI calculators look deceptively simple — a couple of inputs and a formula. But once you add metric/imperial switching, a split ft+inches input, and live reactive updates, there are a few patterns worth thinking through. Here's how we built the one in Ultimate Tools. The Two Formulas BMI has different formulas depending on the unit system: Metric — weight in kg, height in metres: BMI = weight(kg) / height(m)² Imperial — weight in lbs, height in inches: BMI = 703 × wei