BMI Calculator

Calculate your Body Mass Index instantly — find your weight category, healthy weight range, and personalised guidance

Your BMI Result

Enter your height and weight, then click Calculate.

BMI Classification Table
BMI RangeCategoryHealth Risk
< 18.5UnderweightMalnutrition, osteoporosis
18.5 – 24.9Normal WeightLowest risk
25.0 – 29.9OverweightModerate risk
30.0 – 34.9Obese Class IHigh risk
35.0 – 39.9Obese Class IIVery high risk
≥ 40.0Obese Class IIIExtremely high risk

Frequently Asked Questions

BMI (Body Mass Index) measures body fat based on height and weight. Formula: BMI = weight (kg) ÷ height² (m²). For imperial: BMI = (weight in lbs × 703) ÷ height² (inches). It was developed by Adolphe Quetelet in the 1830s.

BMI is a useful screening tool but doesn't account for muscle mass, bone density, or fat distribution. Athletes may show a high BMI due to muscle. Older adults may have a "normal" BMI with excess body fat. Always consult a doctor for a full health assessment.

For adults aged 18–65, the WHO considers a BMI of 18.5 to 24.9 healthy. Below 18.5 is underweight; 25–29.9 is overweight; 30+ is obese. For Asian populations, the WHO suggests lower thresholds (overweight at 23, obese at 27.5).

Healthy weight range = 18.5 × height² to 24.9 × height² (height in metres). For example, at 170 cm: 53.5 kg – 72.0 kg. This calculator shows your personal range automatically after calculating.

For children and teenagers (2–19), BMI is interpreted using age- and sex-specific percentiles, not fixed cutoffs. A healthy BMI percentile is between the 5th and 85th. This calculator is designed for adults — use CDC BMI-for-age charts for children.

BMI uses only height and weight, so it cannot distinguish between muscle mass and fat mass. Muscle is denser and heavier than fat, meaning a highly muscular athlete may register as "overweight" or even "obese" on the BMI scale despite having very low body fat. For athletes and bodybuilders, body fat percentage measurement (via DEXA scan or skinfold calipers) is a more meaningful health indicator. Always consult a healthcare professional for a full assessment.

Research shows that people of Asian descent face higher health risks at lower BMI values than Western populations. The WHO recommends using lower thresholds for Asian populations: overweight at BMI 23+ and obese at BMI 27.5+, compared to 25 and 30 for the general population. Countries including Japan, China, Singapore, and India have adopted these adjusted cutoffs in clinical practice. Consult a healthcare professional for guidance tailored to your background.

Waist-to-height ratio (WHtR) is calculated by dividing your waist circumference by your height — both in the same unit. A healthy WHtR is generally below 0.5 (i.e., waist less than half your height). Some researchers argue WHtR is a better predictor of cardiovascular risk than BMI because it specifically measures abdominal fat, which is the most metabolically harmful type. Combining BMI with WHtR gives a more complete picture of health risk.

In some countries and insurance markets, BMI is used as a screening tool that can influence life insurance or health insurance premiums. Applicants with a BMI above 30 or below 17.5 may face higher premiums or additional medical reviews. This practice is controversial, as BMI does not fully capture individual health status. If your BMI is in an elevated range, additional health data (blood pressure, cholesterol, fitness level) can often provide important context for insurers.

A healthy weight range is derived from the BMI range of 18.5 to 24.9, applied to your height. The formula is: weight = BMI × height² (in metres). For example, at 170 cm, a healthy weight falls between approximately 53.5 kg and 72.0 kg. This calculator shows your personal healthy weight range automatically. Remember that this is a statistical guideline — muscle mass, frame size, and age can all affect what is optimal for you individually.

About This BMI Calculator

This free BMI Calculator uses the standard WHO formula to instantly classify your weight. It supports both metric (cm/kg) and imperial (ft–in/lbs) inputs. You get your BMI score, health category, and the healthy weight range for your height.

Healthy Weight by Height (Metric)

HeightHealthy Range (kg)
155 cm44.5 – 59.9 kg
160 cm47.4 – 63.7 kg
165 cm50.3 – 67.7 kg
170 cm53.5 – 72.0 kg
175 cm56.7 – 76.3 kg
180 cm60.0 – 80.7 kg
185 cm63.3 – 85.2 kg

Healthy Weight by Height (Imperial)

HeightHealthy Range (lbs)
5'0"97 – 130 lbs
5'3"107 – 141 lbs
5'6"118 – 154 lbs
5'9"128 – 168 lbs
6'0"140 – 183 lbs
6'3"152 – 199 lbs

Standards & References

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