Enter your height and weight to see your BMI and ideal body weight.
Your BMI
0 kg/m²
- Category
- –
- Adjusted body weight
- –
- Actual weight vs ideal
- –
- Healthy weight range
- –
| Formula | Ideal weight (kg) | (lb) |
|---|
BMI and ideal body weight are screening and dosing aids, not measures of health. They don’t account for muscle mass, body shape, age or ethnicity beyond the reference chosen.
Ideal Body Weight and BMI Calculator
This calculator gives you two of the most widely used body-size measures in one place: your body mass index (BMI), and your ideal body weight (IBW) worked out with four established formulas. It also shows an adjusted body weight for drug dosing and the weight range that corresponds to a healthy BMI for your height.
How BMI is calculated
BMI = weight (kg) ÷ height (m)²
Weight in pounds and height in feet and inches are converted to kilograms and metres first.
| BMI (kg/m²) | WHO standard category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity class I |
| 35.0 – 39.9 | Obesity class II |
| 40.0 and above | Obesity class III |
BMI for Asian populations
A WHO expert consultation found that many Asian populations have a higher risk of type 2 diabetes and cardiovascular disease at lower BMIs than European populations. It kept the international WHO categories but identified additional public-health action points at 23.0, 27.5 and 32.5. When you choose the “Asian populations” reference, the calculator labels BMI 23.0–27.4 as increased risk, 27.5–32.4 as high risk, and 32.5 and above as very high risk, and shows a healthy range of BMI 18.5–22.9.
Ideal body weight formulas
Ideal body weight formulas estimate a “reference” weight from height and sex. They were designed to help dose drugs and calculate kidney function in clinical practice, not to set a personal weight goal. All four use the number of inches over 5 feet (60 in):
| Formula | Men | Women |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg per inch | 45.5 kg + 2.3 kg per inch |
| Robinson (1983) | 52 kg + 1.9 kg per inch | 49 kg + 1.7 kg per inch |
| Miller (1983) | 56.2 kg + 1.41 kg per inch | 53.1 kg + 1.36 kg per inch |
| Hamwi (1964) | 48 kg + 2.7 kg per inch | 45.4 kg + 2.3 kg per inch |
The four formulas give similar results because they trace back to the same height–weight tables. The Devine formula is the most commonly used in clinical practice, so the calculator highlights it. The formulas are defined for adults 152.4 cm (5 ft) or taller and aren’t shown below that height.
Adjusted body weight
For people well above their ideal weight, some drugs are dosed on an adjusted body weight rather than actual weight: adjusted weight = IBW + 0.4 × (actual weight − IBW). If actual weight is at or below ideal weight, actual weight is used. Only use adjusted weight for drugs whose dosing guidance says to.
Limitations of BMI
- It doesn’t distinguish muscle from fat, so it can misclassify athletes and people with low muscle mass.
- It says nothing about where fat is stored. Waist circumference adds useful information about health risk.
- Its categories are population-level guides, and risk varies with ethnicity, age and other health factors.
- It isn’t valid for children, who need age- and sex-specific centile charts.
Frequently asked questions
What is a healthy BMI?
For most adults the WHO healthy range is 18.5 to 24.9. For Asian populations, the range 18.5 to 22.9 is used as the low-risk band.
Which ideal body weight formula is best?
They give similar answers. Devine is the most widely used in clinical practice, especially for drug dosing, which is why it’s highlighted.
Is ideal body weight a weight I should aim for?
Not necessarily. The equations were created for clinical calculations, and a healthy weight for one person can differ from the formula.
Why doesn’t the calculator show ideal body weight for short heights?
The formulas are defined for adults 5 ft (152.4 cm) and taller. Below that they extrapolate poorly, so the calculator shows BMI and healthy range only.
Can I use this for children?
No. Children’s BMI has to be compared with age- and sex-specific centile charts, such as those from the CDC or WHO.
Medical disclaimer
This calculator provides general reference values for adults. BMI and ideal body weight are not diagnoses and do not replace a clinical assessment of health or nutrition. If you have concerns about your weight, talk to a doctor or registered dietitian.
Sources & references
- Pai MP, Paloucek FP. “The origin of the ‘ideal’ body weight equations.” Annals of Pharmacotherapy, 2000. pubmed.ncbi.nlm.nih.gov/10981254
- WHO Expert Consultation. “Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies.” The Lancet, 2004. pubmed.ncbi.nlm.nih.gov/14726171
- World Health Organization. Obesity and overweight fact sheet. who.int
- Centers for Disease Control and Prevention. Adult BMI categories. cdc.gov