BMI Calculator & Health Advisor

Anam Shaikh
2026-06-23

Developing Data Products - Week 4 Assignment

The Problem - Why Does BMI Matter?

The Scale of the Issue

Over 1 billion adults worldwide are obese (WHO, 2022)
Most people don't know their BMI or what it means
Existing calculators give a number with no context

What's Missing?

Metric & imperial unit flexibility
Personalised, actionable health recommendations
Visual representation of where you stand
Built-in documentation - no external links needed

Meet the App - BMI Calculator & Health Advisor

plot of chunk bmi-scale

Key Features: Metric & Imperial units | Reactive results | Visual BMI gauge | Built-in docs | WHO-based advice

How It Works - App Architecture

Inputs (ui.R)

Widget	Input Type	Purpose
textInput	Text box	User name
radioButtons	Radio	Unit system
numericInput	Number	Weight and Height
selectInput	Dropdown	Biological sex
actionButton	Button	Trigger calculation

Server Logic (server.R)

bmi_data <- eventReactive(input$calculate, {
  bmi <- weight_kg / (height_m ^ 2)
  category <- case_when(
    bmi < 18.5 ~ "Underweight",
    bmi < 25   ~ "Normal weight",
    bmi < 30   ~ "Overweight",
    TRUE       ~ "Obese"
  )
})

Try It Now - & Thank You!

App URL: https://anam-shaikh.shinyapps.io/BMI_Calculator/

Why use this app?

Works in your browser — no R knowledge needed
Metric & imperial units with personalised greeting
Instant visual feedback on the BMI scale
WHO-based health recommendations