BMI Calculator

Calculate your BMI and age-adjusted ideal weight range.

Age (Years):

Gender:

Height (cm):

Current Weight (kg):

Your BMI

Suggested BMI

Ideal Weight (kg)

Weight to Goal

This gauge represents your calculated BMI value. A healthy BMI dynamically changes based on your age.

How This Tool Works

Operation: The Body Mass Index (BMI) Calculator computes BMI using the standard formula adopted by the World Health Organization (WHO):

BMI = Weight (kg) / Height² (m²)

For Imperial measurements: BMI = (Weight in lbs / Height in inches²) × 703

The tool supports input in both Metric (kg/cm) and Imperial (lbs/ft/in) units. After computing the BMI value, it categorises the result according to WHO standards:

< 16.0: Severe underweight
16.0 – 16.9: Moderate underweight
17.0 – 18.4: Mild underweight
18.5 – 24.9: Normal weight
25.0 – 29.9: Overweight
30.0 – 34.9: Obese Class I
35.0 – 39.9: Obese Class II
≥ 40.0: Obese Class III (Severe)

The tool also calculates healthy weight range for the given height: the weight corresponding to BMI 18.5 (lower bound) and BMI 24.9 (upper bound).

Key Benefits of Using the BMI Calculator

Complete health data privacy: Your height, weight, and other body measurements are processed entirely in your browser. No personal health information is ever transmitted or stored — essential since body metrics are sensitive personal data that could be misused if leaked.
Dual unit support (Metric & Imperial): Switch seamlessly between kg/cm and lbs/ft/in. Height can be entered as total cm or feet + inches — accommodating users from any country without requiring manual conversions.
Healthy weight range guidance: Beyond the single BMI number, the tool shows the healthy weight range for your height, giving you a target to aim for rather than just a diagnostic label.

Practical Real-World Use Cases

Health-conscious individuals tracking progress: A person on a weight management journey can periodically check their BMI — watching it move from the 'overweight' into the 'normal' range over weeks or months — using the same local calculator each time without data exposure.
Fitness trainers assessing clients: A personal trainer can quickly compute a client's BMI during a consultation to establish a baseline metric, discussing healthy weight ranges and setting realistic goals — all without storing the client's body data on a server.
Medical students learning assessments: A medical student practising anthropometric assessments can input various height/weight combinations to see which BMI category each falls into, building intuition for patient assessments.

Frequently Asked Questions (FAQ)

Is BMI an accurate measure of health?

BMI is a useful screening tool but has limitations. It does not distinguish between muscle and fat mass — athletes with high muscle mass may be classified 'overweight' despite having very low body fat. It also does not account for fat distribution (waist circumference).

Are the WHO categories applicable to all ethnicities?

WHO categories are population-level standards. Some studies suggest that Asians may have higher health risks at lower BMIs. The WHO has suggested lower overweight thresholds (BMI ≥ 23) for certain Asian populations as a public health guideline.

Can I use this for children or teenagers?

Adult BMI categories (18.5–24.9 normal) do not apply to children. For individuals under 18, BMI should be interpreted using age and sex-specific percentiles from WHO or CDC growth charts.