1.75 m and 70 kg
70 ÷ 1.75² = 70 ÷ 3.0625 = 22.9. That is inside the healthy band of 18.5 to 24.9.
At that height the healthy range runs from about 56.7 kg to 76.3 kg — a spread of nearly 20 kg, which is a useful reminder of how wide the band is.
BMI calculator
Enter your height and weight in whichever units you use. You get your BMI, the category it falls in, and the weight range that would put you in the healthy band at your height.
BMI is a screening indicator, not a diagnosis. It is for information only and does not replace advice from a healthcare professional.
Result
Fill in the fields to see your result.
How it works
Body mass index divides weight by the square of height. Squaring the height is what makes the index roughly comparable between a short person and a tall one: body mass grows faster than height, and the square is a reasonable — though imperfect — correction for that.
The index was designed in the nineteenth century to describe populations, not individuals, and that is still what it does best. Across thousands of people, average BMI correlates well with average body fat. For any single person it can be badly wrong, because it has no way of knowing whether a kilogram is muscle, fat, bone or water.
That is why this page also shows your healthy weight range in your own units and the ponderal index, which divides by the cube of height and distorts less at extreme heights. Neither replaces a measurement of body composition, but both give more context than a single number.
Formulas used
Body mass index
BMI = m ÷ h²
- m
- mass in kilograms
- h
- height in metres
In pounds and inches the equivalent is BMI = 703 × lb ÷ in². This calculator converts to metric first, which avoids the rounding that the 703 factor introduces.
Healthy weight range for a given height
from 18.5 × h² to 24.9 × h²
Worked examples
5 ft 10 in and 190 lb
Converted, that is 1.778 m and 86.2 kg, giving a BMI of 27.3 — the overweight band.
The healthy range at that height ends around 168 lb. But if those 190 lb belong to a trained athlete, the number says very little.
Assumptions and limits
- The WHO adult thresholds are used, without ethnicity-specific adjustment.
- Entries are converted to kilograms and metres before the calculation, so metric and imperial inputs give identical results.
- The healthy range is derived from BMI 18.5 to 24.9 at the height you entered.
- No account is taken of age, sex, body composition, pregnancy or medical conditions.
Frequently asked questions
What is a healthy BMI?
The World Health Organization places the healthy band between 18.5 and 24.9 for adults. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 and above is classed as obesity.
Some health authorities use lower thresholds for people of South Asian, Chinese and Japanese descent, because cardiometabolic risk rises at a lower BMI in those populations.
Why does BMI say I am overweight when I am fit?
Because muscle is denser than fat. A person who trains seriously carries more mass at the same height, and BMI counts every kilogram the same way. Athletes routinely score in the overweight band with low body fat.
If that describes you, a body-fat estimate or a waist measurement will tell you more than BMI.
Does BMI work for children?
Not with these thresholds. Children and teenagers are assessed against growth charts that compare them with others of the same age and sex, because body composition changes rapidly during growth. Use a paediatric percentile chart instead.
Is waist measurement better than BMI?
For predicting cardiometabolic risk, waist circumference and waist-to-height ratio generally perform better, because they capture where fat is stored. Abdominal fat carries more risk than the same amount on hips or thighs.
A simple rule of thumb: keep your waist under half your height.
Sources
- World Health Organization — Body mass index classification for adults
- Quetelet A. (1832), the original formulation of the index
Updated