BMI Calculator
Calculate your Body Mass Index, see your healthy weight range, and understand your result.
Waist-to-Hip Ratio Calculator
A more precise measure of abdominal fat and cardiovascular risk
For men, a ratio above 0.90 indicates central obesity. Your ratio of 0.86 is approaching increased risk.
What is BMI (Body Mass Index)?
Body Mass Index (BMI) is a numerical value calculated from your weight and height. It's one of the most widely used screening tools in medicine for estimating whether a person's weight falls within a healthy range. Healthcare providers across Ireland and worldwide use BMI as a quick, initial indicator of potential weight-related health risks. It applies to adult men and women.
How is BMI calculated?
The BMI formula divides your weight in kilograms by your height in metres squared:
For example, if you weigh 75 kg and are 1.73 m tall: 75 ÷ (1.73 × 1.73) = 75 ÷ 2.99 = 25.1 — just into the overweight category according to WHO classifications.
BMI Categories & Health Risks
BMI in Ireland — Key Statistics
Ireland has one of the highest rates of overweight and obesity in Europe. If your BMI places you in the overweight or obese range, you're far from alone — but it does mean taking your result seriously. If weight-related health issues are affecting your ability to work, you may be entitled to statutory sick leave under the Sick Leave Act 2022.
Limitations of BMI
💪 Can't tell muscle from fat
BMI measures weight relative to height only. Two people with identical BMI scores can have vastly different body compositions. Someone with lean muscle is in a fundamentally different position to someone carrying visceral fat.
👥 Varies by sex, age & ethnicity
Women carry ~10% more body fat than men at the same BMI. People of South Asian, Chinese, and other Asian backgrounds face elevated health risks at lower BMI thresholds than standard classifications suggest.
🏃 Athletes & active people
Athletes often register as overweight or obese on BMI purely because muscle is denser than fat. Pregnant women, children, and older adults are also poor candidates for standard BMI assessment.
📏 Better measures alongside BMI
Waist circumference (>94 cm men, >80 cm women = increased risk), waist-to-hip ratio, and body fat percentage all provide more precise insight into cardiovascular and metabolic risk than BMI alone.
