BMI Calculator
Enter your height and weight to see your body mass index, the category it falls in, the weight range considered healthy for your height and your standard weight — calculated instantly in your browser.
Your result
WHOYour BMI
—
Enter your height and weight to see your BMI.
- Healthy weight range
- BMI 18.5 to under 25 for your height
- Standard weight · BMI 22
- vs. you
- BMI Prime
- Ponderal Index
- kg/m³
Adult categories do not apply under age 18. For children and teens, BMI is interpreted with age- and sex-specific growth percentiles — please consult a paediatrician.
For information only. BMI is a screening measure and does not diagnose health or body fat. Consult a qualified professional for medical advice.
Method
How BMI Calc Atelier works
BMI compares your weight with the square of your height, giving a single number that can be read against population-based categories.
Measure
Enter your height and weight in centimetres and kilograms, or in feet, inches and pounds.
Calculate
Your weight is divided by your height in metres squared. The result updates as you type.
Interpret
Your BMI is placed on the WHO or Japanese (JASSO) scale, alongside your healthy weight range and standard weight.
The formula
- Metric
- BMI = kg ÷ m²
- Imperial
- BMI = 703 × lb ÷ in²
- Example
- 170 cm and 65 kg → 65 ÷ (1.70 × 1.70) = 22.5
Also calculated
- Standard weight
- Weight at BMI 22, the value associated with the lowest rate of illness in Japanese studies.
- BMI Prime
- Your BMI divided by 25, the upper limit of the healthy range. Below 1.0 means you are under that limit.
- Ponderal Index
- Weight divided by height cubed (kg/m³). It varies less with height, so it is sometimes used for very tall or short people.
Reference
BMI charts and tables
Two classification systems are in common use. The WHO scale is used internationally; Japan uses the JASSO scale, which starts obesity at BMI 25 because health risks rise at a lower BMI in Asian populations.
WHO
Japan (JASSO)
| Category | BMI (kg/m²) |
|---|---|
| Severe thinness | < 16 |
| Moderate thinness | 16 – < 17 |
| Mild thinness | 17 – < 18.5 |
| Normal | 18.5 – < 25 |
| Overweight (pre-obese) | 25 – < 30 |
| Obese class I | 30 – < 35 |
| Obese class II | 35 – < 40 |
| Obese class III | ≥ 40 |
| Category | BMI (kg/m²) |
|---|---|
| Underweight | < 18.5 |
| Normal weight | 18.5 – < 25 |
| Obesity (grade 1) | 25 – < 30 |
| Obesity (grade 2) | 30 – < 35 |
| Obesity (grade 3) | 35 – < 40 |
| Obesity (grade 4) | ≥ 40 |
Healthy weight by height
| Height | Healthy range | Standard weight |
|---|---|---|
| 140 cm4′7″ | 36.3 – 48.8 kg80 – 108 lb | 43.1 kg95 lb |
| 145 cm4′9″ | 38.9 – 52.4 kg86 – 115 lb | 46.3 kg102 lb |
| 150 cm4′11″ | 41.6 – 56.0 kg92 – 124 lb | 49.5 kg109 lb |
| 155 cm5′1″ | 44.4 – 59.8 kg98 – 132 lb | 52.9 kg117 lb |
| 160 cm5′3″ | 47.4 – 63.7 kg104 – 141 lb | 56.3 kg124 lb |
| 165 cm5′5″ | 50.4 – 67.8 kg111 – 149 lb | 59.9 kg132 lb |
| 170 cm5′7″ | 53.5 – 72.0 kg118 – 159 lb | 63.6 kg140 lb |
| 175 cm5′9″ | 56.7 – 76.3 kg125 – 168 lb | 67.4 kg149 lb |
| 180 cm5′11″ | 59.9 – 80.7 kg132 – 178 lb | 71.3 kg157 lb |
| 185 cm6′1″ | 63.3 – 85.2 kg140 – 188 lb | 75.3 kg166 lb |
| 190 cm6′3″ | 66.8 – 89.9 kg147 – 198 lb | 79.4 kg175 lb |
Healthy weight range (BMI 18.5–24.9) and standard weight (BMI 22) by height
Perspective
What BMI can and cannot tell you
BMI is quick, inexpensive and useful for comparing populations, but it does not measure body fat directly. Muscular people can have a high BMI with little fat, while older adults may have a normal BMI with reduced muscle and more fat.
Waist circumference, blood pressure, blood tests and lifestyle all add context. Use your BMI as a starting point for a conversation, not as a verdict.
Risks linked to a high BMI
- High blood pressure
- Type 2 diabetes
- Abnormal blood lipids
- Coronary heart disease and stroke
- Sleep apnoea
- Osteoarthritis of the knees and hips
Risks linked to a low BMI
- Nutritional deficiencies and anaemia
- Reduced bone density
- Weakened immunity
- Menstrual irregularities
- Loss of muscle strength
FAQ
Frequently asked questions
Short answers to the questions people most often ask about BMI.
What is a healthy BMI?
For adults, a BMI from 18.5 up to (but not including) 25 is considered the healthy range under both the WHO and the Japanese JASSO standards.
How is BMI calculated?
Divide your weight in kilograms by the square of your height in metres. In imperial units, multiply your weight in pounds by 703 and divide by the square of your height in inches.
Why does Japan classify BMI 25 as obesity?
Studies in Japan found that obesity-related conditions such as diabetes and high blood pressure increase from around BMI 25, so JASSO defines obesity from that point. The WHO calls a BMI of 25–29.9 “overweight”.
What is standard weight?
Standard weight is the weight that gives a BMI of 22 for your height (22 × height in metres²). BMI 22 has been associated with the lowest rate of illness in Japanese research.
Is BMI accurate for athletes, older adults or pregnant women?
Not fully. BMI cannot distinguish muscle from fat, tends to underestimate body fat in older adults, and is not meant for assessing weight during pregnancy. Other measures and professional advice are needed in these cases.
Can I use this calculator for children?
The calculator will show the number, but adult categories do not apply under 18. A child's BMI is judged against age- and sex-specific growth percentiles.
Is my data stored anywhere?
No. The calculation happens entirely in your browser. Your values only appear in the page address if you choose to copy a result link.