NexoPhysique.AI
BMI calculator
Work out your Body Mass Index and understand what it tells you — and, more importantly, what it doesn't.
Knowing how much to eat is one step. NexoPhysique.AI builds your periodised training, your meal plan with meals split out, and adjusts everything week by week as you progress — with AI body analysis.
Try 7 days for R$ 16,90How BMI is calculated
The formula is simple and nearly two centuries old:
BMI = weight(kg) ÷ height(m)²
Someone at 80 kg and 1.75 m has a BMI of 80 ÷ (1.75 × 1.75) = 26.1.
World Health Organization ranges
- Under 18.5 — underweight
- 18.5 to 24.9 — healthy weight
- 25.0 to 29.9 — overweight
- 30.0 to 34.9 — obesity class I
- 35.0 to 39.9 — obesity class II
- 40.0 or more — obesity class III
Where BMI fails
BMI doesn't distinguish muscle from fat, and that limitation voids the index in plenty of real cases.
A man at 1.75 m and 88 kg with 12% body fat has a BMI of 28.7 — overweight by the table, when in fact he's in good shape. The other way round, someone at 1.75 m and 68 kg with 30% body fat has a BMI of 22.2 — healthy weight — despite little muscle.
It also says nothing about where the fat sits, and distribution matters more for cardiovascular risk than the total.
What to look at instead
Three measures beat BMI: waist circumference, waist-to-height ratio (below 0.5 is the target) and photos at the same angle every four weeks. Scales swing with water and glycogen; the photo doesn't lie.
Frequently asked questions
No. Above-average muscle mass reads as overweight or obese without any excess fat. For athletes, body fat percentage and circumferences are far more useful.
The WHO healthy range runs from 18.5 to 24.9. But 'ideal' depends on body composition, age and health history.
The formula and ranges are the same. What differs is healthy body fat percentage, naturally higher in women.
See a doctor or dietitian for a full assessment including bloods and body composition. A high BMI is a reason to investigate, not a conclusion about your health.