What a BMI number means: three real examples

165 cm and 78 kg

BMI = 78 ÷ 1.65² = 28.7, in the overweight range (25 to 29.9). For this height the range the WHO calls healthy is 50.4 to 67.8 kg, so the gap to the top of it is about 10 kg.

Losing 5% of body weight (about 4 kg) already brings measurable health benefits for many people; the calorie calculator estimates the daily intake for a steady pace.

185 cm and 95 kg, a rugby player

BMI = 95 ÷ 1.85² = 27.8, also overweight on paper. But BMI cannot tell muscle from fat, and a muscular athlete can have little body fat at this figure. Waist size is a useful second check: guidelines often flag a waist above about 94 cm for men and 80 cm for women.

170 cm and 52 kg

BMI = 52 ÷ 1.70² = 18.0, just under 18.5: mild thinness in the WHO table. The healthy range for this height starts at 53.5 kg. Being underweight carries its own risks, and unexplained weight loss is worth discussing with a doctor.

When not to use BMI

For children and teenagers BMI is read against growth charts for age and sex, not the adult table. It is less reliable during pregnancy and in older adults, and some health bodies use lower cut-offs for people of Asian descent. Use the BMI calculator as a screening number, not a diagnosis.