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BMI Calculator

Calculate your Body Mass Index and find your healthy weight range for your height.

Whole feet (e.g. 5)

Remaining inches (0–11)

Your weight in pounds.

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BMI Calculator Formula

BMI is calculated from height and weight:

BMI = weight (kg) ÷ height² (m²)

For imperial inputs, convert first:

height (m) = total inches × 0.0254 | weight (kg) = pounds × 0.453592

How to Use This Calculator

  1. Choose your unit system: Imperial (feet, inches, pounds) or Metric (centimeters, kilograms).
  2. Enter your height and weight using the fields that appear.
  3. Click Calculate BMI to see your BMI, category, and healthy weight range.

Frequently Asked Questions

What is a healthy BMI?

According to the World Health Organization, a BMI between 18.5 and 24.9 is considered normal weight. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese.

Is BMI accurate for everyone?

BMI is a useful screening tool, but it has limitations. It uses the same formula for all adults regardless of sex, even though women naturally carry 6–11% more body fat than men at the same BMI. It also does not distinguish between muscle and fat, so athletes with high muscle mass may have an elevated BMI that does not reflect excess body fat. For a more complete picture of your energy needs, try our BMR calculator to estimate your daily calorie requirements. Use BMI as a general guideline rather than a definitive health assessment.

How do I calculate BMI in imperial units?

Convert your height to total inches (feet × 12 + remaining inches), then to meters by multiplying by 0.0254. Convert your weight from pounds to kilograms by multiplying by 0.453592. Then divide weight (kg) by height (m) squared.

What is the healthy weight range for my height?

The healthy weight range corresponds to a BMI of 18.5 to 24.9 (Normal weight). This calculator shows your personal healthy weight range based on the height you enter.

What are the full WHO BMI classifications?

The World Health Organization classifies adult BMI (age 20+) into the following categories, used for both men and women:

ClassificationBMI range (kg/m²)
Severe Thinness< 16
Moderate Thinness16 – 17
Mild Thinness17 – 18.5
Normal18.5 – 25
Overweight25 – 30
Obese Class I30 – 35
Obese Class II35 – 40
Obese Class III> 40

Does BMI apply to children and teenagers?

BMI is calculated the same way for children, but the interpretation differs. For ages 2-19, BMI is plotted on age- and sex-specific growth charts and expressed as a percentile. This calculator is designed for adults (age 20+).

Further Reading

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