A practical screening measure
BMI is inexpensive, repeatable and widely used to group adult weight-for-height values. Healthcare professionals consider it alongside medical history, examination and other measurements.
Adult body mass index
BMI Calculator
Calculate your adult BMI in seconds using kilograms and centimetres or pounds, feet and inches. See the standard category and weight range for your height.
Height and weight
Calculate your BMI
For adults aged 20 and older.
Private by design. Your height, weight and result stay in this browser.
Your measurements
Enter height and weight
Your result
Adult BMI
Healthy weight
Your BMI is within the standard healthy-weight category for adults.
22.9
Standard healthy-weight range
56.7–76.3 kg
Position relative to that range
Within the range
Calculation
70 ÷ 1.75²
BMI is a screening measure, not a diagnosis. It does not directly measure body fat or account for muscle mass, pregnancy, body composition or where fat is carried.
Understand the result
What BMI can—and cannot—tell you
BMI is a quick comparison of weight with height. It can start a useful health conversation, but it cannot describe an individual’s health on its own.
Body composition matters
BMI cannot separate body fat from muscle, bone or fluid. A muscular athlete may have a high BMI, while someone inside the healthy category can still have other health risks.
Not for every situation
Do not apply these adult categories to children or teenagers. Pregnancy, an eating disorder, limb loss, marked muscle mass or a condition affecting height can also require professional assessment.
Adult BMI categories
Standard ranges for adults aged 20 and older
The calculator uses the standard adult categories published by the CDC. The healthy-weight estimate applies the 18.5 and 24.9 boundaries to your height.
For a more reliable calculation
- Measure height without shoes and stand upright against a wall.
- Use a level, firm floor and a calibrated scale where possible.
- Wear light clothing and measure under similar conditions when tracking changes.
- Discuss unexpected changes or concerns with a qualified healthcare professional.
| Category | BMI (kg/m²) |
|---|---|
| Underweight | Below 18.5 |
| Healthy weight | 18.5 to <25 |
| Overweight | 25 to <30 |
| Obesity, class 1 | 30 to <35 |
| Obesity, class 2 | 35 to <40 |
| Obesity, class 3 | 40 or above |
Guidance references: CDC adult BMI categories and WHO obesity and overweight guidance.
BMI questions
BMI Calculator FAQ
How is BMI calculated?
Metric BMI is weight in kilograms divided by height in metres squared. With US customary units, BMI is weight in pounds divided by height in inches squared, multiplied by 703.
What is a healthy BMI for an adult?
The standard adult healthy-weight category is a BMI from 18.5 to less than 25. A BMI below 18.5 is underweight, 25 to less than 30 is overweight, and 30 or higher is in the obesity range.
What is a healthy weight for my height?
The calculator applies BMI values of 18.5 and 24.9 to your entered height to show the corresponding standard adult healthy-weight range. This is a screening range, not a personal target or medical recommendation.
Does BMI measure body fat?
No. BMI compares weight with height but does not directly measure body fat or distinguish fat from muscle and bone. Athletes and people with high muscle mass can therefore have a high BMI without having high body fat.
Can children and teenagers use this BMI calculator?
No. This calculator uses adult categories intended for people aged 20 and older. BMI for children and teenagers must be interpreted using age- and sex-specific growth-chart percentiles.
Should BMI be used during pregnancy?
BMI calculated from current pregnancy weight is not interpreted with the standard adult categories. Ask a qualified healthcare professional about appropriate weight assessment before, during and after pregnancy.
Does the calculator support kilograms, pounds, centimetres and feet?
Yes. Choose Metric for kilograms and centimetres, or US units for pounds, feet and inches. Switching systems converts the values already entered.
Does Bobek save my height, weight or BMI?
No. The calculation runs locally in your browser. Bobek does not receive or store the height, weight or BMI values you enter.