WeightLogBMI calculator
Enter your height and weight to see your body mass index, its category and the healthy weight range for your height.
Your BMI
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–- Healthy weight for your height
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For adults aged 20 and over. BMI can't tell muscle from fat, so read it as a rough guide, not a diagnosis.
What the numbers mean
These follow the World Health Organization's adult cut-offs, grouped the same way as in the WeightLog app.
| Category | BMI |
|---|---|
| Underweight | below 18.5 |
| Healthy weight | 18.5 to 24.9 |
| Overweight | 25 to 29.9 |
| Obesity | 30 to 39.9 |
| Severe obesity | 40 and above |
How it's calculated
BMI = weight in kg ÷ (height in m)²
For example, 70 kg at 175 cm gives 70 ÷ 1.75² = 22.9. Pounds, stones, feet and inches are converted first, with the same factors as the app: 1 kg = 2.205 lb, 1 kg = 0.15747 st and 1 in = 2.54 cm. The result is rounded to one decimal place.
The healthy weight range
It's the weight that would put your BMI between 18.5 and 25 at your height. At 170 cm that's 53.5 to 72.2 kg.
What BMI doesn't show
- Muscle and bone. A muscular person can land in the overweight range.
- Where the fat sits. The waist-to-height ratio adds that view. Waist-to-height ratio calculator
- Ethnic background. Some health services use lower cut-offs for certain ethnic backgrounds.
- Children and teenagers. Under 20, BMI is read against growth charts for age and sex, so this calculator isn't the right tool.
Your BMI, updated with every weigh-in
WeightLog recalculates your BMI each time you log your weight, and a home screen widget keeps it in sight.
More calculators
Body fat
An estimate from neck, waist and hip measurements with the U.S. Navy method.
Daily calories
Your basal metabolic rate and the calories to maintain, lose or gain weight.
Calories burned
The energy you use in 25 activities, from walking and running to cycling and swimming.
Heart rate zones
Your estimated maximum heart rate and five training zones in beats per minute.
Waist-to-height ratio
How your waist compares with your height: a quick check of fat around the middle.
