Health & Fitness
BMI Calculator
Check your body mass index from height and weight.
Result
Example with the values filled in above
Body mass index
23.1
Category: Healthy weight
Target BMI 22: 71.3 kg (3.7 kg above target)
| Height | 180 cm | 1.8 m |
|---|---|---|
| Weight | 75 kg | Metric input |
| Healthy BMI range | 59.9-80.7 kg | BMI 18.5-24.9 |
| Target difference | 3.7 kg | 3.7 kg above target |
Change any value and press Calculate for your own result.
Calculating…
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Weight at the BMI category lines, by height
- BMI 30
- BMI 25
- BMI 18.5
Show the numbers
| Height | BMI 30 | BMI 25 | BMI 18.5 |
|---|---|---|---|
| 150 cm | 67.5 kg | 56.3 kg | 41.6 kg |
| 155 cm | 72.1 kg | 60.1 kg | 44.4 kg |
| 160 cm | 76.8 kg | 64.0 kg | 47.4 kg |
| 165 cm | 81.7 kg | 68.1 kg | 50.4 kg |
| 170 cm | 86.7 kg | 72.2 kg | 53.5 kg |
| 175 cm | 91.9 kg | 76.6 kg | 56.7 kg |
| 180 cm | 97.2 kg | 81.0 kg | 59.9 kg |
| 185 cm | 102.7 kg | 85.6 kg | 63.3 kg |
| 190 cm | 108.3 kg | 90.3 kg | 66.8 kg |
| 195 cm | 114.1 kg | 95.1 kg | 70.3 kg |
| 200 cm | 120.0 kg | 100.0 kg | 74.0 kg |
How BMI is calculated
Body mass index relates your weight to your height to give a quick screening measure of body size. The calculator accepts metric or imperial units — feet, inches, pounds, and ounces are converted to meters and kilograms first — and also shows what you would weigh at a target BMI of your choice.
Formula
BMI = weight (kg) ÷ height (m)²
Weight at target BMI = target × height (m)²
Worked example
At 75 kg and 180 cm: height is 1.80 m, so BMI = 75 ÷ (1.80 × 1.80) = 75 ÷ 3.24 = 23.1 — inside the healthy range. To reach a target BMI of 22, the weight would be 22 × 3.24 = 71.3 kg.
BMI categories (adults)
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obesity range |
Where BMI falls short
Because BMI only uses height and weight, it can misclassify people whose body composition is unusual. A muscular athlete may land in the "overweight" range despite low body fat, while an older adult who has lost muscle can read as "healthy" while carrying excess fat. BMI cut-offs were derived largely from adult populations of European descent and fit less well for other groups — some health bodies use a lower overweight threshold (around 23) for people of South Asian heritage. It also does not apply to children and teens, who need age- and sex-specific percentile charts.
Measurements that add context
Pair BMI with a waist measurement — carrying fat around the middle raises health risk independently of BMI, and a waist over about 94 cm (37 in) for men or 80 cm (31.5 in) for women is a common warning line. Waist-to-height ratio (keeping your waist under half your height) is another quick check. Trends over time matter more than a single reading, so track the direction of change rather than fixating on one number.
BMI is a screening tool, not a diagnosis — it cannot tell muscle from fat. For energy needs, pair it with the BMR calculator and the calorie calculator.
BMI Calculator — frequently asked questions
How is BMI calculated?
BMI is weight in kilograms divided by height in meters squared: BMI = kg ÷ m². A person weighing 75 kg at 1.80 m has a BMI of 75 ÷ 3.24 ≈ 23.1. Imperial entries are converted to metric first.
What is a healthy BMI?
For most adults, a BMI of 18.5 to 24.9 is considered the healthy range. Below 18.5 is classed as underweight, 25 to 29.9 as overweight, and 30 or above as the obesity range.
Is BMI accurate for everyone?
BMI is a useful screening tool but not a diagnosis. It does not distinguish muscle from fat, so very muscular people can score "overweight" while being lean, and it applies differently to children and during pregnancy. Talk to a healthcare professional about what your number means.
What does the target BMI field do?
It shows the body weight that would give you the BMI you choose, using target BMI × height². That makes it easy to translate a BMI goal into a concrete weight goal in kilograms.