Body measurements

Body mass index with its WHO category, and body surface area by the Mosteller, Du Bois or Haycock formula.

BMI: 22.9; Normal weight
BSA, mosteller: 1.84 m²
BSA, du bois: 1.85 m²
BSA, haycock: 1.85 m²

Installation

bunx shadcn@4.22.1 add https://organui.com/r/body-measurements.json

This adds lib/body-measurements.ts, with no dependencies.

Usage

import {
  bmiCategory,
  bodyMassIndex,
  bodySurfaceArea,
} from "@/lib/body-measurements"

const bmi = bodyMassIndex(70, 175) // 22.86
bmiCategory(bmi) // "normal"
bodySurfaceArea(70, 175) // 1.84 m², Mosteller
bodySurfaceArea(20, 110, "haycock") // 0.78 m²

API Reference

Body measurements exports
Export	Description
`bodyMassIndex(weightKg, heightCm)`	Weight in kilograms over height in metres squared.
`bmiCategory(bmi)`	The WHO adult category: underweight, normal, overweight, or obesity class I, II or III.
`bmiCategoryLabels`	A label for each category, such as "Obesity class I".
`bodySurfaceArea(weightKg, heightCm, formula?)`	Square metres by "mosteller" (the default), "du-bois" or "haycock", which is often used in children.

Notes

BMI categories apply to adults. Children and adolescents are assessed with BMI-for-age percentiles instead.

Doses calculated from body surface area need clinical review; the formulas differ by a few percent.