BMI Calculator
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Result
BMI = --
Healthy BMI range: 18.5 – 25
The result above is not a diagnosis
BMI = --
Healthy BMI range: 18.5 – 25
The result above is not a diagnosis
The Body Mass Index (BMI) is a widely used health indicator in the United States that helps determine whether a person has a healthy body weight based on their height. It is a simple calculation that provides a quick estimate of body fat levels and potential health risks.
BMI is commonly used by doctors, fitness professionals, and insurance providers as a screening tool. While it does not directly measure body fat, it gives a reliable starting point to assess whether an individual falls into categories such as underweight, normal weight, overweight, or obese.
---The following BMI categories are based on standard guidelines used across the United States and recommended by global health organizations.
| Classification | BMI Range (kg/m²) |
|---|---|
| Severe Thinness | < 16 |
| Moderate Thinness | 16 – 17 |
| Mild Thinness | 17 – 18.5 |
| Normal | 18.5 – 25 |
| Overweight | 25 – 30 |
| Obese Class I | 30 – 35 |
| Obese Class II | 35 – 40 |
| Obese Class III | > 40 |
A BMI chart visually represents how different height and weight combinations impact BMI values. It helps users quickly understand their category and see how small changes in weight can affect their overall health classification.
In general, individuals with a BMI between 18.5 and 25 are considered to be within a healthy weight range. Values below this range may indicate underweight, while higher values indicate overweight or obesity.
---In the United States, BMI for children and teenagers is evaluated differently than for adults. Instead of fixed BMI ranges, results are compared to age- and gender-specific percentiles developed by the CDC.
| Category | Percentile Range |
|---|---|
| Underweight | < 5% |
| Healthy Weight | 5% – 85% |
| At Risk of Overweight | 85% – 95% |
| Overweight | > 95% |
Having a high BMI can increase the risk of several serious health conditions. These risks are widely recognized in the United States healthcare system.
Maintaining a healthy BMI can significantly reduce the likelihood of developing these conditions and improve overall quality of life.
---While much attention is given to obesity, being underweight also carries health risks that should not be ignored.
If BMI is significantly below normal, it may indicate underlying health issues that require medical attention.
---Although BMI is a useful screening tool, it is not a perfect measurement of health. It does not distinguish between fat and muscle mass, which can lead to misleading results in certain cases.
For a more accurate assessment, BMI should be considered along with other health indicators such as body fat percentage, waist circumference, and lifestyle habits.
---BMI is calculated using different formulas depending on the measurement system used.
Metric Formula:
BMI = weight (kg) / height² (m²)
US Formula:
BMI = 703 × weight (lbs) / height² (in²)
---BMI Prime is a more advanced way to interpret BMI results. It compares your BMI to the upper limit of the normal BMI range (25).
Formula: BMI Prime = BMI / 25
A BMI Prime value below 1 indicates a healthy range, while values above 1 indicate overweight or obesity.
---The Ponderal Index (PI) is similar to BMI but is considered more accurate for very tall or very short individuals.
Formula: PI = mass / height³
While BMI remains the most commonly used metric in the United States, the Ponderal Index can provide additional insight in specific cases.