Adult screening tool

BMI Calculator

Calculate body mass index in metric or imperial units, see the standard adult BMI category, estimate your healthy weight range, and learn when regional cutoffs or body fat estimates add better context.

This adult BMI calculator is a screening tool, not a diagnosis. It also includes reverse BMI guidance and Asia-Pacific context because BMI thresholds can be interpreted differently by population and clinical setting.

Calculate Your BMI

Enter your height and weight, then choose the unit system you prefer.

Adult BMI ranges are generally used for ages 20+.
Fast Get your BMI and estimated healthy weight range in seconds.
Clear See the standard adult BMI categories used by major health references.
Practical Use BMI as a starting point before looking deeper at body fat and waist size.
Free No signup, no download, and no extra tools required.

Adult BMI Categories

Standard adult BMI ranges commonly used by CDC, NHLBI, and other health references.

Underweight

< 18.5

Weight status is below the standard adult healthy range.

Healthy weight

18.5 - 24.9

For most adults, this is the normal BMI range.

Overweight

25.0 - 29.9

BMI is above the healthy range and may indicate higher health risk.

Obesity

30.0+

Higher BMI levels are associated with higher risk of weight-related conditions.

Category BMI range What it usually means
Underweight < 18.5 Weight status is below the standard adult healthy range.
Healthy weight 18.5 - 24.9 For most adults, this is the normal BMI range.
Overweight 25.0 - 29.9 BMI is above the healthy range and may indicate higher health risk.
Obesity 30.0+ Higher BMI levels are associated with higher risk of weight-related conditions.

Example BMI Calculations

These examples cover normal BMI calculation, reverse BMI healthy range, and why regional guidance may change the conversation.

Example 1

170 cm + 65 kg
BMI 22.5 • Healthy weight

A BMI around 22.5 falls within the standard healthy range for adults.

Example 2

175 cm + 82 kg
BMI 26.8 • Overweight

This BMI is above the healthy range and may be a prompt to check waist size and body fat.

Example 3

5 ft 9 in + 165 lb
BMI 24.4 • Healthy weight

An imperial example that still lands in the standard healthy BMI category.

Reverse BMI example

170 cm + BMI 18.5-24.9
Healthy range about 53.5-72.0 kg

A reverse BMI calculator asks what weight range matches a target BMI. Use it as a planning range, not a strict goal.

Asia-Pacific context

172 cm + 70 kg
BMI 23.7 • Standard healthy, but regional caution may start lower

Some Asia-Pacific references use lower action points for overweight risk, so Singapore or Hong Kong users may need local clinical guidance.

How BMI Is Calculated

BMI uses only height and weight. That makes it convenient, low-cost, and easy to use at scale, but it also cannot tell the difference between fat mass and muscle mass.

Metric formula
BMI = weight (kg) / height (m)^2
Imperial formula
BMI = weight (lb) / height (in)^2 × 703
Useful for adults: Adult BMI categories are generally used for people aged 20 and older. Children and teens use BMI percentiles instead of the adult ranges above.

Limitations of BMI

BMI is convenient, but trustworthy interpretation needs context: reverse BMI ranges, body composition, waist size, age, and in some regions lower public-health action points.

BMI does not measure body fat directly

A high BMI may reflect fat, muscle, or both. A normal BMI also does not guarantee low body fat.

Athletic and muscular adults may be overestimated

People with higher muscle mass can have a higher BMI without having excess body fat.

Some groups need more context

Older adults, pregnant people, and those with unusual body composition may need a more tailored interpretation.

Waist size still matters

Abdominal fat distribution can add health risk information that BMI alone cannot capture.

Reverse BMI gives a range, not a prescription

A target BMI range can estimate a weight range for your height, but it does not know your muscle mass, medical history, training goal, or preferred body composition.

Asia-Pacific cutoffs may be lower

Some Asian health references use lower BMI action points than the standard WHO adult categories. Use local Singapore, Hong Kong, or clinician guidance if it applies to you.

Waist guidance: Health references commonly note higher risk when waist circumference is above 35 inches for women or above 40 inches for men. Waist size is not a diagnosis either, but it helps add context.
Need a visual comparison? Use the body fat visualizer guide to understand how photo-based body fat estimates differ from BMI.

BMI Calculator FAQ

BMI stands for body mass index. It is a screening measure based on height and weight that helps estimate whether an adult falls into a standard weight category.

For most adults, a BMI from 18.5 to 24.9 is considered a healthy or normal range.

No. BMI uses only height and weight. Body fat percentage tries to estimate how much of your body is fat tissue. BMI is useful for screening, but body fat gives a more direct view of body composition.

BMI can be less informative for children and teens, pregnant people, older adults, and very muscular adults. In those cases, it is better to combine BMI with body fat, waist circumference, or medical advice.

A reverse BMI calculator estimates the weight range that matches a target BMI for your height. On this page, the result panel shows the healthy weight range for BMI 18.5 to 24.9. It is useful for planning, but it should not replace body composition or medical context.

Often, yes. Standard adult BMI categories are widely used, but some Asia-Pacific public-health references use lower action points for overweight or risk screening. If you live in Singapore, Hong Kong, or another region with local guidance, use this calculator as a baseline and follow local clinical advice.

BMI is only a starting point

For a body-composition signal that goes beyond height and weight, compare your BMI with the AI body fat estimator from photo.

Try the AI Body Fat Estimator