HandyTools Hub

BMI Calculator

Calculate your Body Mass Index and daily calorie needs

How to Use

  1. Enter your weight — Use the slider or number input. Toggle between kilograms (kg) and pounds (lbs) with one click.
  2. Enter your height — Choose metric (cm) or imperial (feet/inches). The chart updates in real time as you adjust.
  3. View your BMI — Your score appears instantly along with a color-coded category bar (underweight, normal, overweight, obese).
  4. Calculate BMR — Optionally enter your age and sex. The tool calculates your Basal Metabolic Rate using the Mifflin-St Jeor Equation and shows your healthy weight range.

Features

  • Instant BMI calculation — Body Mass Index computed from height and weight with real-time visual feedback — no button pressing needed.
  • Dual unit support — Metric (kg/cm) and imperial (lbs/ft/in) systems with a single toggle.
  • Color-coded category chart — Highlights where your score falls, plus the healthy weight range for your height.
  • BMR calculation — Basal Metabolic Rate using the Mifflin-St Jeor Equation with age and sex inputs.
  • 100% client-side privacy — All processing happens in your browser — your data never leaves your device.
  • Mobile-friendly design — Large touch targets for easy adjustment on phones and tablets.

Use Cases

  • Health self-assessment: Checking your own BMI as part of a general fitness checkup.
  • Weight management: Estimating daily calorie needs by combining BMR with activity levels.
  • Family health: Helping family members quickly assess their weight category during a health discussion.
  • Goal setting: Using the healthy weight range as a reference for diet or exercise planning.

Frequently Asked Questions

What is BMI and how is it calculated?

BMI (Body Mass Index) is a measure of body fat based on height and weight. For metric: BMI = weight(kg) / height(m)^2. For imperial: BMI = weight(lb) / height(in)^2 * 703.

What is BMR and how is it calculated?

BMR (Basal Metabolic Rate) is calories burned at rest. The calculator uses the Mifflin-St Jeor Equation: BMR = 10*weight(kg) + 6.25*height(cm) - 5*age + (5 male, -161 female).

Is BMI accurate for everyone?

BMI is a useful screening tool but has limitations. It doesn't distinguish muscle from fat, so muscular people may get high BMI scores. Factors like age, ethnicity, and body composition also affect accuracy. Consult a healthcare professional for a complete assessment.