Calculate your Body Mass Index (BMI) to assess if your weight is in a healthy range. Used worldwide as a screening tool for weight categories.
Last updated: March 2026
Medical disclaimer: This calculator provides an estimate only and is for informational and educational purposes only. It is not a medical device and is not a substitute for professional medical advice, diagnosis, or treatment.
BMI is a screening tool and does not directly measure body fat percentage. Individual factors like age, sex, muscle mass, bone density, and fitness level affect health risks. Use results with caution and consult a qualified healthcare professional before making medical, training, or nutrition decisions.
Body Mass Index (BMI) is a measurement that correlates body weight with height to assess whether weight is in a healthy range. It applies to adult men and women and provides a simple numeric measure to screen for weight categories: underweight, normal weight, overweight, or obese. While it doesn't directly measure body fat percentage, it correlates reasonably well with body fat for most people and is used by healthcare professionals worldwide as a general screening tool.
Metric Units (kg, cm):
Imperial Units (lbs, inches):
Calculate BMI for a person who is 175 cm tall and weighs 70 kg:
Although BMI is a widely used and useful indicator of healthy body weight, it has important limitations that should be understood. BMI is an estimate that cannot account for body composition—the ratio of muscle, bone, and fat in the body.
BMI cannot distinguish between muscle and fat. Since muscle is denser than fat, very muscular individuals—such as bodybuilders, athletes, or those with high fitness levels—may have a high BMI despite having low body fat percentage. Conversely, sedentary individuals with significant body fat may fall within a "normal" BMI range.
BMI is further influenced by age, sex, ethnicity, and activity level. For example:
BMI should therefore be considered alongside other health metrics and body composition measurements rather than used as the sole indicator of health.
The same factors that limit BMI accuracy in adults apply to children. Additionally, height growth and sexual maturation can influence both BMI and body fat levels. BMI is a more reliable indicator of excess body fat in obese children than in overweight children, whose elevated BMI may result from either increased fat or fat-free mass (water, organs, muscle, bone).
For these reasons, children's BMI should be compared to age and sex-specific growth charts rather than standard adult categories.
Despite these limitations, BMI is fairly indicative of body fat for approximately 90–95% of the population and remains a useful screening tool when used alongside other health assessments and professional medical guidance.
BMI is a screening tool and has limitations. It doesn't account for muscle mass, bone density, or body composition. Athletes with high muscle mass may have a high BMI but low body fat. Consult healthcare professionals for a complete assessment.
For most adults, a BMI between 18.5 and 24.9 is considered healthy. However, ideal BMI can vary based on age, sex, ethnicity, and individual factors. Some populations may have different healthy ranges.
BMI is calculated the same way for children, but the interpretation differs. Children's BMI is compared to growth charts and expressed as percentiles for their age and sex. Use a pediatric BMI calculator for children under 20.
BMI helps identify potential health risks. Being significantly underweight or overweight is associated with increased risk of various health conditions including heart disease, diabetes, and certain cancers. It's one tool among many for assessing health.
Yes, muscle weighs more than fat, so very muscular individuals (like bodybuilders or athletes) may have a high BMI despite having low body fat. BMI doesn't distinguish between muscle and fat mass.
For most people, checking BMI every few months is sufficient. If you're actively trying to lose or gain weight, monthly checks can help track progress. Focus on trends over time rather than day-to-day fluctuations.
The calculation is universal, but interpretation may vary. Some Asian populations may have higher health risks at lower BMI values. The WHO uses modified BMI cutoffs for certain ethnic groups.
If your BMI is outside the normal range, consult a healthcare provider. They can assess your overall health, body composition, and risk factors to create an appropriate plan. Don't make drastic changes without medical guidance.
Overweight individuals face increased risks of high blood pressure, heart disease, stroke, type 2 diabetes, sleep apnea, osteoarthritis, certain cancers, and mental health issues. These risks increase substantially with higher BMI values.
Yes, being underweight can lead to malnutrition, anemia, osteoporosis, weakened immunity, hormonal imbalances, and increased infection risk. In women, severe underweight can affect fertility and pregnancy outcomes.
No. BMI should be considered alongside other measurements like waist circumference, blood pressure, cholesterol, blood sugar, and overall fitness level. Consult with a healthcare provider for a comprehensive health assessment.
BMI is calculated using only height and weight, so it can't distinguish between muscle and fat. This is why some very fit individuals may have a high BMI while sedentary individuals may have a "normal" BMI despite excess body fat.
Being overweight increases the risk of numerous serious diseases and health conditions. According to the CDC, these include:
Maintaining a BMI below 25 kg/m² significantly reduces these health risks, though consulting with a healthcare provider is recommended for personalized guidance.
Being underweight carries its own set of health risks and concerns that should not be overlooked:
In some cases, being underweight indicates an underlying condition such as an eating disorder or chronic illness. If you believe you are underweight without an obvious cause, consult a healthcare provider.
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