How to use this calculator
- Pick your unit system: Metric (centimeters and kilograms) or Imperial (feet, inches, and pounds).
- Enter your height and weight. Decimals are fine (e.g. 172.5 cm or 160.5 lb).
- Hit Calculate to see your BMI, your WHO weight category, and the healthy weight range for your height.
- If your current weight falls outside the healthy range, the calculator also shows how far above or below it you are.
How BMI is calculated
Body mass index is your weight divided by the square of your height. The formulas for the two unit systems are:
Metric: BMI = weight (kg) ÷ height (m)² · Imperial: BMI = 703 × weight (lb) ÷ height (in)²
For example, someone who is 175 cm tall and weighs 70 kg has a BMI of 70 ÷ (1.75 × 1.75) = 22.9. In imperial terms, a person who is 5 ft 9 in (69 inches) and weighs 160 lb has a BMI of 703 × 160 ÷ 69² = 23.6. This calculator rounds to one decimal place and classifies the result using the WHO international standard:
| BMI range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal (healthy) weight |
| 25 – 29.9 | Overweight |
| 30 – 34.9 | Obese (Class I) |
| 35 – 39.9 | Obese (Class II) |
| 40 and above | Obese (Class III) |
The healthy weight range works the same formula in reverse: 18.5 × height (m)² up to 24.9 × height (m)². At 175 cm, that's roughly 56.7 to 76.3 kg (about 125 to 168 lb). The calculator converts this range into whichever units you selected.
Good to know
BMI is a screening tool, not a diagnosis. Because it uses only height and weight, BMI can't distinguish muscle from fat or tell you where fat is stored. A muscular athlete may score as "overweight" while carrying little body fat, and someone with a normal BMI can still have an unhealthy body-fat percentage. Treat BMI as a quick first check, not a verdict.
Different cutoffs exist for some populations. The WHO Asia-Pacific guidelines use lower action points — 23 for overweight and 25 for obesity — because at the same BMI, people of Asian descent tend to carry more body fat and face higher metabolic risk. Some countries' health services also apply adjusted thresholds for children, teens, and older adults. This page uses the standard WHO international cutoffs for adults.
Pair BMI with waist circumference. Abdominal fat is a stronger predictor of metabolic disease than overall weight. As a common rule of thumb, a waist above 40 inches (102 cm) for men or 35 inches (88 cm) for women signals elevated risk even when BMI looks fine. Body-composition scans and body-fat percentage measurements give an even fuller picture.
This result is for general reference only and is not medical advice. Talk to a doctor or registered dietitian before making decisions about weight management.
BMI chart: healthy weight by height
The table below applies the WHO healthy range (BMI 18.5–24.9) to common heights, with weights rounded to the nearest whole kilogram and pound. Find the row closest to your height for a quick reference, or enter your exact measurements above for a precise answer.
| Height | Healthy weight (kg) | Healthy weight (lb) |
|---|---|---|
| 150 cm (4 ft 11 in) | 42 – 56 kg | 92 – 124 lb |
| 155 cm (5 ft 1 in) | 44 – 60 kg | 98 – 132 lb |
| 160 cm (5 ft 3 in) | 47 – 64 kg | 104 – 141 lb |
| 165 cm (5 ft 5 in) | 50 – 68 kg | 111 – 149 lb |
| 170 cm (5 ft 7 in) | 53 – 72 kg | 118 – 159 lb |
| 175 cm (5 ft 9 in) | 57 – 76 kg | 125 – 168 lb |
| 180 cm (5 ft 11 in) | 60 – 81 kg | 132 – 178 lb |
| 185 cm (6 ft 1 in) | 63 – 85 kg | 140 – 188 lb |
| 190 cm (6 ft 3 in) | 67 – 90 kg | 147 – 198 lb |
Setting a weight goal from this chart? The Percentage Calculator makes it easy to track your progress as a percentage of the way there.
Frequently asked questions
What is a healthy BMI?
Under the WHO international classification, a BMI between 18.5 and 24.9 is considered the normal (healthy) range for adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese. These cutoffs apply to adults aged 20 and over, regardless of sex.
How is BMI calculated in pounds and inches?
With imperial units the formula is BMI = 703 × weight (lb) ÷ height (in)². For example, someone who is 5 ft 9 in (69 inches) and weighs 160 lb has a BMI of 703 × 160 ÷ 69² = 23.6. The 703 factor converts the result to the same scale as the metric formula, kg/m².
Is BMI accurate for athletes and muscular people?
Not always. BMI only uses height and weight, so it cannot tell muscle from fat. A muscular athlete can register as overweight or even obese while carrying very little body fat. If that describes you, pair BMI with a body-fat percentage measurement or a waist circumference check for a more realistic picture.
Why do some Asian countries use different BMI cutoffs?
Research has shown that at the same BMI, people of Asian descent tend to carry more body fat and face higher risks of type 2 diabetes and cardiovascular disease. For that reason the WHO Asia-Pacific guidelines set lower action points: 23 for overweight and 25 for obesity. This calculator uses the standard WHO international cutoffs, so results may differ from calculators localized for Asian countries.
How do I find the healthy weight range for my height?
Reverse the BMI formula: multiply 18.5 and 24.9 by your height in meters squared. If you are 175 cm tall, the healthy range is 18.5 × 1.75² = 56.7 kg up to 24.9 × 1.75² = 76.3 kg. This calculator does the conversion for you automatically in either metric or imperial units.