BMI calculator
Calculate your body mass index and see which range your weight falls into.
Your BMI
-
BMI (Body Mass Index) is your weight in kilograms divided by your height in metres squared. It is a quick, rough indicator - it cannot tell muscle from fat, so it overestimates for very muscular people.
WHO ranges: below 18.5 - underweight, 18.5-24.9 - normal, 25-29.9 - overweight, 30 and above - obese. If you are working on your weight, a multi-week trend says far more than a single reading.
This calculator is approximate and educational - it does not replace advice from a doctor or dietitian.
Frequently asked questions
Is BMI enough to judge a healthy weight?
No. BMI is a quick rough indicator, but it does not show body composition, waist size, age or health status. Treat it as a starting point.
When can BMI be misleading?
Most often in very muscular people, pregnancy, older adults and when fluid retention is significant. In those cases, compare BMI with waist measurements, weight trend and professional advice.
How often should I calculate BMI?
You do not need it daily. Recheck BMI after a meaningful weight change or every few weeks, and follow your weight trend day to day.
Does BMI work the same for women and men?
The formula is the same, but interpretation can differ because average body composition differs. BMI is not a full assessment.
Is BMI suitable for children?
Not in this simple adult version. Children and teenagers use age- and sex-based percentile charts, best discussed with a clinician.
Does a low BMI always mean a problem?
Not always, but a very low result can point to undernutrition or illness. If weight loss is unintentional, get medical advice.
Does a high BMI always mean excess fat?
Not always. Muscular people can have a high BMI with low body fat, but for most adults it remains a useful warning signal.
What is better than a single BMI number?
Weight trend, waist size, how you feel, lab results and regular observation. One number rarely tells the whole story.
Can BMI change quickly?
It changes with weight, but multi-week changes matter more. Daily weight swings often come from water, salt and food volume.
Is BMI reliable for very short or tall people?
It works mathematically, but can be less precise at height extremes. In those cases, look beyond BMI.
Should I track BMI while using GLP-1 medication?
It can help as an occasional marker, but weight trend, dose history, symptoms and doctor-ready notes matter more.
What BMI range is considered normal?
For adults, the classic normal range is 18.5-24.9. It is a population range, not a personal diagnosis.