Calculate your body mass index, see where it sits on the WHO scale and get the healthy weight range for your height. Then read why it is only a starting point.
kg
cm
Your BMI27.6Overweight
Ponderal index16.5kg/m³Fairer for very tall or short people
27.6
UnderweightHealthyOverweightClass IClass IIClass III
Healthy weight range52 kg – 70 kgBMI 18.5 – 24.9 for your height
To reach the healthy range7.7 kgto lose
BMI is a population screening tool, not a diagnosis. It cannot tell muscle from fat, and healthy ranges differ by ethnicity and age. If your BMI is high but your body-fat percentage is low, trust the body fat.
How BMI is calculated
BMI is your weight in kilograms divided by your height in metres squared. A 70 kg person who is
1.75 m tall has a BMI of 70 ÷ (1.75 × 1.75) = 22.9. It was devised in the 1830s as a statistical
tool and became a clinical screening measure because it is free, fast and correlates with health
outcomes across large groups.
What it cannot tell you
BMI does not know how much of your weight is muscle, where your fat is stored, or how fit you
are. Two people with the same BMI can have completely different health profiles. If your BMI is
above 25, the most useful next step is a body-fat estimate and a waist measurement: a waist of
more than half your height is a stronger warning sign than BMI alone.
Using it well
Use the healthy weight range as a broad guide, then set a goal that reflects your build and your
body-fat percentage rather than the arithmetic midpoint. When you are ready, the calorie calculator will show you how to get there.
Frequently asked questions
What is a healthy BMI?
+
For adults, the World Health Organization defines 18.5–24.9 as the healthy range, 25–29.9 as overweight and 30 or above as obesity. Health risk rises gradually, not at a cliff edge.
Is BMI accurate?
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At population level it tracks health risk well. For an individual it can mislead: muscular people read as overweight, and older adults can read as healthy while carrying excess fat. Pair it with waist circumference or a body-fat estimate.
Does BMI differ by ethnicity?
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Yes. Health risks appear at lower BMIs in people of South Asian, Chinese and some other backgrounds; guidelines in the UK and elsewhere use 23 and 27.5 as the thresholds for those groups.
What is the ponderal index?
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Weight divided by height cubed. It is fairer than BMI for very tall or very short people, whose BMI is skewed by the square-of-height formula. A healthy range is roughly 11–15 kg/m³.
Ethereal provides general educational information and estimates only. It is not medical advice and
does not replace an assessment by a doctor or registered dietitian. Do not use it if you are under
18, pregnant, or have a history of disordered eating without professional guidance.
Read the full disclaimer.