Body Mass Index Calculator
Find your BMI in seconds and see where you sit on the WHO scale, plus the healthy weight range for your height.
Awaiting Data
Enter your details and tap Calculate to see your results appear here.
Healthy weight range appears here.
What BMI Measures
Body Mass Index compares your weight to your height. Created in the 1830s by Adolphe Quetelet, it gives a single number that screens for underweight, healthy weight, and excess weight across large groups.
Doctors reach for BMI because it costs nothing and takes seconds. Your number maps to a category that flags possible health risk, from low bone density at the low end to heart and metabolic strain at the high end.
Remember one limit: BMI counts total weight, not what that weight is made of. Muscle and fat read the same on the scale, so very lean, muscular people can score high without carrying excess fat.
How to Use This Calculator
- Choose metric or US units with the toggle.
- Enter your height in the first field.
- Enter your current weight in the second field.
- Tap Calculate to see your BMI, category, and healthy range.
The Formula Used
- weight
- Your body weight in kilograms. Pounds convert automatically in US mode.
- height
- Your standing height in metres. Centimetres and inches convert automatically.
Square your height in metres, then divide your weight by that result. A 72 kg person at 1.75 m scores 72 ÷ 3.0625, which rounds to 23.5.
Understanding Your Results
Tips to Improve Your Number
- Build meals around protein and vegetables to stay full on fewer calories.
- Walk 8,000 to 10,000 steps a day to raise your energy burn without strain.
- Lift weights twice a week so the weight you keep is muscle, not fat.
- Drink water before meals to curb mindless snacking.
- Track progress monthly, not daily, since weight swings with water and food.
Where BMI helps, and where it falls short
Useful at a glance, BMI flags possible weight risk across large groups for almost no effort. Clinicians reach for it as a fast screen, and so can you. Limits exist, though. Muscle outweighs fat, so a strong athlete may read as overweight, while a slim person can hide excess fat. Treat the result as a first clue, never a final verdict.
Round out the story with partner tools. Measure fat directly on the Body Fat Calculator, check fat placement with the Waist to Hip Ratio, and view shape through the Body Roundness Index. Wanting a target weight? The Ideal Weight Calculator sets a sensible range.
Reaching a healthier BMI
Small, steady changes win the long game. Move most days, build meals around protein and vegetables, and let your daily calorie needs set a gentle deficit. Sleep and stress weigh as much as food, so guard both. For official ranges and their meaning, the World Health Organization and the CDC keep clear, current pages. Our article on metrics beyond BMI goes further.
Frequently Asked Questions
The WHO marks 18.5 to 24.9 as healthy for most adults. Below that is underweight, 25 to 29.9 is overweight, and 30 or above is obese.
It can overstate fat in muscular bodies, since muscle weighs more than fat. Pair BMI with a body fat reading for a clearer result.
Yes, the formula is identical. Women average more body fat at the same BMI, so treat the number as a broad screen.
Scientific References
- World Health Organization. (2024). Body mass index (BMI). WHO Global Health Observatory.
- Centers for Disease Control and Prevention. (2024). About Adult BMI. CDC Division of Nutrition, Physical Activity, and Obesity.
- Quetelet, A. (1842). A Treatise on Man and the Development of his Faculties. Edinburgh: William and Robert Chambers.
- Nuttall, F. Q. (2015). Body Mass Index: Obesity, BMI, and Health: A Critical Review. Nutrition Today, 50(3), 117–128.