BMI Calculator - Calculate Your Body Mass Index Free

Calculate your BMI instantly with our free calculator. Get personalized health recommendations based on your weight and height

How to Use the BMI Calculator

1

Choose Units

Select metric (kg/cm) or imperial (lbs/in) units using the toggle.

2

Enter Details

Input your current weight and height in the respective fields.

3

Get Results

View your BMI score, category, and personalized health recommendations instantly.

What is a BMI Calculator?

Our free BMI Calculator helps you determine your Body Mass Index quickly and accurately. Whether you prefer metric (kg/cm) or imperial (lbs/in) units, get instant results with personalized health recommendations based on your BMI category.

Body Mass Index is a widely-used screening tool that relates your weight to your height. While it's not a perfect measure of health, BMI provides a useful starting point for understanding your weight category and potential health risks associated with being underweight, normal weight, overweight, or obese.

How Does the BMI Calculator Work?

BMI is calculated using a simple formula that divides your weight by the square of your height. For metric units, it's weight (kg) / height (m)². For imperial units, it's weight (lbs) / height (in)² × 703.

Metric Formula

BMI = weight (kg) / [height (m)]²

Example: 70 kg / (1.75 m)² = 22.9

Imperial Formula

BMI = [weight (lbs) / height (in)²] × 703

Example: (154 lbs / 69²) × 703 = 22.7

Understanding BMI Categories

BMI values are categorized into ranges that indicate different weight statuses. Understanding these categories can help you assess your health and set appropriate goals.

Underweight

< 18.5

May indicate malnutrition or health issues

Normal Weight

18.5 - 24.9

Healthy weight range for most adults

Overweight

25 - 29.9

Higher risk for health problems

Obese

≥ 30

Significantly increased health risks

Why Use Our BMI Calculator?

Using a BMI calculator provides several advantages for health monitoring and fitness planning:

  • Quick Health Screening: Get an instant assessment of your weight category and understand potential health risks.
  • Track Progress: Monitor changes in your BMI over time as you work toward your fitness goals.
  • Set Realistic Goals: Determine your target weight range based on BMI categories for healthier living.
  • Universal Standard: BMI is recognized worldwide by healthcare professionals as a screening tool.

When to Use a BMI Calculator

Health Monitoring

Track your body mass index over time to monitor your health progress and weight management goals.

Fitness Planning

Use BMI as a baseline metric to create effective fitness and nutrition plans tailored to your body type.

Medical Assessment

Healthcare professionals use BMI for initial health screenings and risk assessments for weight-related conditions.

Weight Goals

Determine your ideal weight range and set realistic weight loss or gain targets based on BMI categories.

Frequently Asked Questions

BMI (Body Mass Index) is a measure of body fat based on height and weight. It's calculated by dividing weight in kilograms by height in meters squared (kg/m²), or weight in pounds divided by height in inches squared, multiplied by 703.

A healthy BMI typically falls between 18.5 and 24.9. Below 18.5 is considered underweight, 25-29.9 is overweight, and 30 or above is classified as obese. However, BMI should be one of several health indicators.

BMI is a useful screening tool but not perfect. It doesn't account for muscle mass, bone density, age, or gender differences. Athletes with high muscle mass may have high BMI but low body fat.

This calculator is designed for adults (18+ years). Children and teens require age and gender-specific BMI-for-age percentile charts because body composition changes significantly during growth.

For general health monitoring, checking BMI monthly or quarterly is sufficient. If you're actively working on weight management, weekly or bi-weekly checks can help track progress without becoming obsessive.

BMI doesn't distinguish between muscle and fat, doesn't account for distribution of fat, and may not be accurate for pregnant women, elderly individuals, or certain ethnic groups with different body compositions.

Consult with a healthcare provider who can assess your overall health, including body composition, diet, and lifestyle. They can provide personalized recommendations for achieving a healthy weight.

The BMI calculation is the same for both genders, but interpretation may vary slightly. Women naturally have more body fat than men, so the same BMI may represent different body compositions.

Higher BMI is associated with increased risk of conditions like heart disease, diabetes, and high blood pressure. However, BMI should be combined with other health indicators like waist circumference and blood tests.

BMI is a simple calculation using height and weight, while body fat percentage measures the actual proportion of fat in your body. Body fat percentage is more accurate but requires specialized equipment to measure.