Calculate your Body Mass Index instantly in metric or imperial units. See your BMI category, healthy weight range for your height, and understand what your number really means.
Calculate Your BMI
feetinches
23.6
Normal Weight
Healthy BMI range: 18.5 – 24.9
BMI Scale
1518.5253040
Underweight
< 18.5
Normal
18.5–24.9
Overweight
25–29.9
Obese
≥ 30
Healthy weight range for your height
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What Is BMI and How Is It Calculated?
Body Mass Index (BMI) is a numerical value calculated from your height and weight. It was developed by Belgian mathematician Adolphe Quetelet in the 1830s and has since become the most widely used screening tool for weight categories in clinical practice worldwide.
Below 18.5 — Underweight: May indicate malnutrition, eating disorder, or other health issues. Consult a doctor.
18.5 to 24.9 — Normal/Healthy: Associated with lowest health risk in most population studies.
25.0 to 29.9 — Overweight: Increased risk of cardiovascular disease, type 2 diabetes, and hypertension.
30.0 and above — Obese: Significantly elevated risk for multiple chronic conditions. Class 1: 30–34.9, Class 2: 35–39.9, Class 3: 40+
BMI Limitations — What It Doesn't Tell You
BMI is a useful starting point but has well-documented limitations that every person should understand before interpreting their result:
It doesn't account for muscle mass
A muscular athlete may register as "overweight" or even "obese" on the BMI scale despite having very low body fat. Conversely, a sedentary person with a normal BMI may carry excess body fat in dangerous locations (particularly around the abdomen) — a condition sometimes called "skinny fat" or metabolic obesity normal weight (MONW).
Age and sex differences
Older adults naturally lose muscle mass and gain fat, so the same BMI carries different health implications at 65 than at 25. Women generally carry more body fat than men at the same BMI. Some research suggests optimal BMI may be slightly higher (23–27) for older adults.
Ethnicity considerations
Studies show that people of Asian descent face elevated metabolic risks at lower BMI levels. The WHO and many Asian health authorities recommend lower cutoff points for Asian populations (23 for overweight, 27.5 for obese) rather than the standard 25/30 thresholds.
💡 Use BMI alongside other measures
For a more complete picture, pair BMI with waist circumference (healthy: <35 inches for women, <40 inches for men), body fat percentage, and cardiorespiratory fitness levels.
Healthy BMI by Age Group
For adults (20+), the standard BMI categories apply regardless of age. For children and teenagers (2–19), BMI is calculated the same way but interpreted differently — using age-and-sex-specific percentile charts from the CDC, as children's body composition changes significantly during development.
Adults (20+): Standard WHO categories apply (18.5–24.9 = healthy)
Older adults (65+): Some evidence suggests 23–28 may be optimal for longevity
Frequently Asked Questions
What is a healthy BMI for women?
The same BMI categories apply to both men and women: 18.5–24.9 is considered healthy. However, women naturally have higher body fat percentages than men at the same BMI. A woman with a BMI of 22 and a man with a BMI of 22 will have different body fat percentages, with the woman typically having 5–8% more fat — which is completely normal and healthy.
Can BMI be too low?
Yes. A BMI below 18.5 is classified as underweight and is associated with health risks including malnutrition, weakened immune function, bone density loss, anemia, and fertility issues. If your BMI is below 18.5, particularly if it's declining, consult a healthcare provider.
How can I lower my BMI?
BMI decreases when you reduce weight or if your height changes (only relevant for growing children). For adults, sustainable weight loss through a modest calorie deficit (300–500 calories/day below maintenance), regular physical activity, adequate sleep, and stress management is the evidence-based approach. Crash diets are generally counterproductive long-term.
Is BMI 25 overweight?
By WHO classification, BMI 25.0 marks the start of the overweight category. However, many healthcare providers consider the range 24.9–26 to be a grey zone where health risk depends heavily on other factors — particularly waist circumference, metabolic markers (blood pressure, cholesterol, blood sugar), and fitness level. A single BMI number should never be viewed in isolation.