⚡ The short version
BMI is weight in kilograms divided by height in metres squared. At 80 kg and 1.75 m that is 26.1 — the overweight band (25–29.9). Healthy is 18.5–24.9.
The calculator
How to use it
- Height and weight — metric or imperial, whichever you know.
- Read the band, not just the number — 26.1 means little until you see it sits in 25–29.9 (overweight).
- Check the healthy range for your height — at 1.75 m it is roughly 56.7–76.3 kg. The tool shows yours.
Worked example
Weight 80 kg, height 1.75 m. Square the height: 1.75² = 3.0625. Divide: 80 ÷ 3.0625 = 26.1. Against the WHO bands — under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obese — that is overweight, about 3.8 kg above the top of the healthy range for this height.
What BMI does not know
- Muscle. A muscular build scores overweight or obese with very little body fat. Athletes should look at body-fat estimates and waist measurement instead.
- Fat distribution. Waist circumference predicts risk better than BMI alone — the NHS flags 94 cm+ for men and 80 cm+ for women as take-action levels.
- Children, pregnancy, old age. Children use percentile charts, not adult bands; pregnancy and age-related muscle loss both break the standard interpretation.
🛠️ Related health tools
📖 Long-form companion: What BMI actually measures.
❓ Frequently asked questions
How is BMI calculated?
BMI = weight in kilograms ÷ height in metres squared. At 80 kg and 1.75 m: 80 ÷ 3.0625 = 26.1, which sits in the overweight band (25–29.9).
What is a healthy BMI?
The WHO healthy range is 18.5–24.9. For someone 1.75 m tall that is roughly 56.7–76.3 kg. Below 18.5 is underweight, 25–29.9 overweight, 30 and above obese.
Why is BMI wrong for athletes?
BMI cannot tell muscle from fat. A muscular rugby player can score overweight or obese with very little body fat. It is a population screening tool, not a body-composition scan — waist measurement and body-fat estimates fill the gap.
Can children use this BMI calculator?
Not directly. Children's BMI is interpreted against age-and-sex percentile charts, not adult bands. This tool uses the adult WHO bands only.