Calculate your Body Mass Index in metric (kg/cm) or imperial (lbs/ft) units and see which category your result falls in.
BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, or distribution of fat. Always consult a healthcare professional for a full assessment.
BMI is a simple ratio of weight to height, squared. In metric units it's your weight in kilograms divided by your height in meters squared; in imperial units, the formula uses a conversion constant (703) to work with pounds and inches instead. The result is a single number that's been used since the 1800s as a quick, low-cost way to flag whether someone's weight falls in a typical range for their height — not to measure body composition directly.
Two people with the same BMI can have very different body compositions. A muscular athlete often scores "overweight" on BMI despite having low body fat, because the formula only sees total weight.
Health researchers increasingly point to fat distribution — particularly around the waist — as more predictive of certain health risks than total BMI alone.
Adult BMI thresholds don't apply well to children, teens, or elderly adults, whose healthy ranges differ for reasons the formula doesn't account for.
Because of these limits, BMI is best used as a quick screening number and a conversation starter with a healthcare provider — not a standalone diagnosis.
BMI is a simple ratio of weight to height squared. It's a quick screening number, not a direct measurement of body fat, muscle, or overall health.
BMI doesn't distinguish between muscle and fat, so athletes and very muscular people often show as "overweight" despite low body fat. It also doesn't account for age, sex, or fat distribution.
Yes. Adult BMI categories don't apply to children and teens, whose healthy range changes with age and sex — pediatric BMI is typically evaluated using growth-chart percentiles instead.