Your BMI (body mass index) is your weight in kilograms divided by your height in meters squared. 75 kg at 1.75 m gives a BMI of 24.5, inside the healthy range. Enter your weight in kilograms, pounds or stone and your height in centimeters or in feet and inches; the calculator shows your category, the healthy weight range for your height and where you stand on the Asian cut-off points.
BMI categories for adults (WHO)
| BMI | Category |
|---|---|
| Under 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25 – 29.9 | Overweight |
| 30 – 34.9 | Obesity class I |
| 35 – 39.9 | Obesity class II |
| 40 or more | Obesity class III |
The calculator places you in a category using the BMI rounded to one decimal, as you see it: 24.96 shows as 25.0 and counts as overweight, so the label always agrees with the number.
Healthy weight for your height
These are the weights that give a BMI of 18.5 to 24.9:
| Height | Healthy weight (kg) | Healthy weight (lb) |
|---|---|---|
| 150 cm (4′11″) | 41.6 – 56.1 | 92 – 124 |
| 155 cm (5′1″) | 44.4 – 59.9 | 98 – 132 |
| 160 cm (5′3″) | 47.3 – 63.8 | 104 – 141 |
| 165 cm (5′5″) | 50.3 – 67.9 | 111 – 150 |
| 170 cm (5′7″) | 53.4 – 72.1 | 118 – 159 |
| 175 cm (5′9″) | 56.6 – 76.4 | 125 – 168 |
| 180 cm (5′11″) | 59.8 – 80.8 | 132 – 178 |
| 185 cm (6′1″) | 63.2 – 85.3 | 139 – 188 |
| 190 cm (6′3″) | 66.7 – 90.0 | 147 – 198 |
| 195 cm (6′5″) | 70.2 – 94.8 | 155 – 209 |
Lower cut-offs for Asian populations
In 2004 a WHO expert consultation reviewed studies from across Asia and found that the risk of type 2 diabetes and heart disease rises at lower BMIs than in European populations. It kept the international categories but proposed additional public-health action points:
| BMI | Risk on the Asian action points |
|---|---|
| Under 18.5 | Underweight |
| 18.5 – 22.9 | Lower risk |
| 23 – 27.4 | Increased risk |
| 27.5 or more | High risk |
The calculator shows both readings, because many people live in one country and come from another. National guidelines in several Asian countries use their own thresholds, so check with your doctor which one applies to you.
BMI Prime
BMI Prime is your BMI divided by 25, the upper limit of the healthy range. A value of 1.00 means you are exactly at that limit; 0.90 means 10% below it; 1.20 means 20% above. It makes the distance to the limit easy to read at a glance.
What BMI does not tell you
BMI was designed to compare populations, not to diagnose individuals. It does not see muscle mass, bone, age, sex or where fat is stored. A rugby player and an inactive person of the same height and weight get the same BMI. Waist circumference adds useful information: health agencies commonly use waist-to-height ratio, aiming for a waist under half your height.
In pounds and inches
If you prefer to calculate by hand in US units: BMI = 703 × pounds ÷ inches². For 165 lb at 5′9″ (69 inches): 703 × 165 ÷ 4,761 = 24.4. The small difference from the metric example is only rounding, since 165 lb is 74.8 kg.
Your numbers are calculated on your device and never leave it. For the same reason, it works offline once zet4u is saved on your device.
Frequently asked questions
How is BMI calculated?
Divide your weight in kilograms by your height in meters squared. 75 kg at 1.75 m: 75 ÷ (1.75 × 1.75) = 24.5. In pounds and inches, multiply by 703: 165 lb at 69 in is 165 × 703 ÷ 69² = 24.4.
What is a healthy BMI?
For adults, the World Health Organization classes 18.5 to 24.9 as a healthy weight, 25 to 29.9 as overweight and 30 or more as obesity.
Are the BMI cut-offs different for Asian people?
A WHO expert consultation (2004) found that many Asian populations face higher health risks at lower BMIs and suggested action points of 23 and 27.5. Several Asian countries use lower thresholds for overweight and obesity.
Does BMI work for athletes?
Not well. BMI cannot tell muscle from fat, so a muscular person can score as overweight while being lean. Waist size or body-fat measurements tell you more.
Can children use this calculator?
No. For children and teenagers, BMI is compared with growth charts for their age and sex. Ask a pediatrician or use a percentile chart.
Sources
- World Health Organization: A healthy lifestyle – WHO recommendations (BMI)
- WHO Expert Consultation: Appropriate body-mass index for Asian populations, The Lancet 2004; 363: 157–163
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