BMI Calculator
Calculate Body Mass Index (BMI) from weight and height.
Formulas
Body Mass Index. WHO-defined universal formula. No jurisdiction dependency.
bmi = weight_kg / (height_m * height_m)
Assumptions and limitations
Scope
Calculate Body Mass Index (BMI) according to the WHO formula: Weight/(Height²). Applicable to adults between 18 and 65 years in general good health, excluding pregnancy and specific medical conditions.
Assumptions
- Body Mass Index. WHO-defined universal formula. No jurisdiction dependency.
Limitations
- Non distingue massa grassa da massa muscolare: atleti con alta muscolatura possono risultare sovrappeso
- Non valido per bambini e adolescenti (richiedono curve di crescita per età e sesso)
- Non è uno strumento diagnostico: è un indicatore di screening di popolazione
- Non adatto a persone anziane (>65 anni) dove la distribuzione corporea cambia
Validation
Approach: Validated by verifying the declared formula and plausibility checks (range, units, edge cases).
Examples
Normal weight adult
- IMC = 70 / (1,75²) = 22,9 → normopeso. Nessun rischio aggiuntivo associato al peso per questa fascia.
Overweight adult
- IMC = 90 / (1,72²) = 30,4 → obesità classe I. Indicazione a valutazione medica e revisione dello stile di vita.
Frequently asked questions
What does a BMI of 26 indicate?
A BMI of 26 falls in the overweight range (25–29.9). It's not a critical condition but it's advisable to monitor diet and physical activity. Cardiovascular risks increase progressively from 25 onwards. Consult your doctor for a personalized assessment.
Is BMI valid for athletes?
No. Athletes with high muscle mass may have an elevated BMI while having little body fat. For professional athletes, it's preferable to directly measure body fat percentage through skinfold measurements or DEXA. BMI is a population indicator, not an individual one.
How to enter height if I know it in centimeters?
Divide centimeters by 100. E.g.: 175 cm = 1.75 m. Enter 1.75 in the height field. Note: a 1 cm error changes BMI by about 0.3 points for a 70 kg person, so enter the value with centimeter precision.