Body Mass Index - BMI Calculator

BMI Calculator

Calculate your Body Mass Index — free, instant, no sign-up required

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Age

years

Gender

Male Female

Height

ft

in

Weight

lbs

Age

years

Gender

Male Female

Height

cm

Weight

kg

Your BMI Result

-- kg/m²

--

1018.52530354045+

Underweight

Normal

Overweight

Obese I

Obese II

Obese III

BMI	--
Category	--
Healthy BMI range	18.5 – 24.9 kg/m²
Healthy weight range	--
BMI Prime	--
Ponderal Index	--

Note for ages under 20: BMI is interpreted differently for children and teens using age- and sex-specific percentile charts. Please consult a healthcare provider for an accurate assessment.

BMI Chart — Height & Weight

Underweight Normal weight Overweight Obese Class I Obese Class II Obese Class III

BMI Classification — Adults (WHO)

BMI Range	Category	Health Risk
Below 18.5	Underweight	Malnutrition risk
18.5 – 24.9	Normal weight	Low (healthy range)
25.0 – 29.9	Overweight	Enhanced risk
30.0 – 34.9	Obese Class I	Medium risk
35.0 – 39.9	Obese Class II	High risk
40.0 and above	Obese Class III	Very high risk

⚠️ BMI is a screening tool, not a diagnosis BMI does not directly measure body fat or account for muscle mass, bone density, age, or fat distribution. Consult a healthcare professional for a complete health assessment.

BMI Calculator — instant, no sign-up, no tracking

What is BMI?

Body Mass Index (BMI) is a number calculated from a person’s height and weight. It provides a simple numeric measure used to classify adults into weight categories associated with health risk levels.

The formula is: BMI = weight (kg) ÷ height (m)². In US units: BMI = 703 × weight (lb) ÷ height (in)².

Limitations of BMI

• Does not distinguish fat mass from muscle mass — athletes often have a high BMI but low body fat.
• Does not account for fat distribution (visceral vs. subcutaneous).
• Can be misleading for elderly people who have lost muscle mass.
• Categories were based on European populations and may not apply equally to all ethnicities.
• For children and teens (under 20), BMI requires age- and sex-specific percentile charts.

BMI Prime & Ponderal Index

BMI Prime is your BMI divided by 25 (the upper limit of normal). A value of 1.0 means you are exactly at the upper edge of the healthy range. Below 0.74 = underweight; above 1.0 = overweight or obese.

Ponderal Index (Corpulence Index) uses the cube of height: PI = weight (kg) ÷ height (m)³. It is more accurate for very tall or short individuals. The healthy range is typically 11–15 kg/m³.