BMI Calculator
Calculate your Body Mass Index (BMI) instantly with metric or imperial units. Free BMI calculator with healthy weight range and category guidance.
A BMI (Body Mass Index) calculator estimates your body fat based on your weight and height using the formula adopted by the CDC and WHO. BMI is a screening tool — not a diagnostic test — widely used by health professionals to categorize weight status into underweight, normal weight, overweight, and obese ranges. This calculator works with metric units (kilograms and centimeters) and also computes your healthy weight range for your height. While BMI does not distinguish between muscle and fat, it is a useful starting point for understanding your weight relative to population health benchmarks. For a fuller picture, combine it with a body fat calculator, waist-to-height ratio, or a conversation with your doctor. This tool is free, private, and runs entirely in your browser.
body
Result
Breakdown
- Healthy Weight Low
- 53.5
- Healthy Weight High
- 72.0
About BMI Calculator
What is bmi calculator?
A BMI (Body Mass Index) calculator estimates your body fat based on your weight and height using the formula adopted by the CDC and WHO. BMI is a screening tool — not a diagnostic test — widely used by health professionals to categorize weight status into underweight, normal weight, overweight, and obese ranges. This calculator works with metric units (kilograms and centimeters) and also computes your healthy weight range for your height. While BMI does not distinguish between muscle and fat, it is a useful starting point for understanding your weight relative to population health benchmarks. For a fuller picture, combine it with a body fat calculator, waist-to-height ratio, or a conversation with your doctor. This tool is free, private, and runs entirely in your browser.
How to use this calculator
- Enter your weight.
- Enter your height.
- Click the "Calculate" button.
- View your result instantly — the main result is displayed prominently at the top with a detailed breakdown below it.
When to use this calculator
- Getting a quick weight-status screening based on height and weight
- Finding the healthy weight range for your height and setting a goal
- Tracking weight changes over time as part of a fitness journey
- Understanding BMI categories as a starting point for health discussions
- Teaching students about population health metrics and the BMI formula
How the calculation works
The BMI formula is weight (kg) divided by height squared (m²): BMI = weight_kg / (height_m)². Height in meters is derived from cm: height_m = height_cm / 100. For example, a person weighing 70 kg at 170 cm tall: height_m = 1.70, BMI = 70 / (1.70 × 1.70) = 70 / 2.89 = 24.2, which falls in the normal weight range (18.5–24.9). Healthy weight range for this height: 18.5 × (1.70)² = 53.5 kg to 24.9 × (1.70)² = 71.9 kg.
Frequently Asked Questions
What is a healthy BMI range?▼
Is BMI accurate for athletes?▼
Related tools
Body Fat Calculator
Estimate your body fat percentage using the U.S. Navy circumference method. Free body fat calculator for men and women with fitness category guidance.
Calorie Calculator
Estimate your daily calorie needs using the Mifflin-St Jeor equation. Free calorie calculator for BMR, TDEE, and weight-loss or gain goals.
Due Date Calculator
Estimate your baby's due date and current pregnancy week using the first day of your last menstrual period. Free due date calculator.
Ovulation Calculator
Predict your ovulation day and fertile window from your last period. Free ovulation calculator for conception and cycle tracking.
Protein Calculator
Estimate your daily protein needs in grams based on weight, activity, and goal. Free protein intake calculator with TDEE and macro split.
Sleep Calculator
Find your ideal bedtime or wake-up time based on 90-minute sleep cycles. Free sleep calculator so you wake up refreshed, not groggy.