175 cm, 70 kg
- Input
- altura 175 cm, peso 70 kg
- Expected output
- IMC 22,9 → peso saudável
70 divided by 1.75 squared (3.0625) gives 22.86, rounded to 22.9, inside the healthy band of 18.5 to 25.
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BMI and weight classification
Body mass index is a two-variable calculation, weight and height, built to compare entire populations, not to diagnose one individual. Knowing the formula and what it leaves out is what separates using the number as a reference from treating it as a verdict on one specific body.
70 divided by 1.75 squared (3.0625) gives 22.86, rounded to 22.9, inside the healthy band of 18.5 to 25.
The same height divisor (3.0625) applied to a lower weight falls below the 18.5 cutoff, classifying as underweight under the WHO band.
Just 25 kg of difference from the first example move the result from the healthy band to obesity class 1, showing how much the denominator (height squared) amplifies every kilogram.
Not by itself. BMI is a screening tool; diagnosis and treatment decisions require clinical assessment, history, exams and other indicators.
Under the WHO classification for adults, 18.5 to 25. Below that is underweight, 25 to 30 is overweight, and from 30 upward the bands split into obesity class 1 (30 to 35), class 2 (35 to 40) and class 3 (40 or above).
The math itself is correct, but the classification can mislead: since the formula only divides total weight by height squared without separating muscle from fat, an athlete with high lean mass can land in "overweight" or "obesity class 1" while carrying a low body fat percentage. It is the classic case where BMI alone is most wrong.
Because a growing body changes composition with age, so the same BMI value can mean different things at age 5 and age 15. Instead of the adult's six fixed bands, child BMI compares the result against an age-in-months-and-sex percentile, using its own dedicated reference table.
No. BMI only uses total weight and height, without measuring how much of that weight is muscle, bone or fat. Body fat percentage is estimated through other methods, such as circumference or skinfold measurements, each with its own margin of error, and it answers a different question than BMI does.
Medical disclaimer: this tool is educational and intended for adults aged 20+. BMI is a population screening measure, not a diagnosis; it does not replace a physician, dietitian or qualified health professional.
This value is within the adult range generally associated with healthy weight. Body composition, waist, lab results and symptoms still matter.
Formula: BMI = weight (kg) ÷ height² (m). Adult classification follows ranges used by WHO/CDC/NIH.
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