Body Mass Index (BMI) Calculator
Easily check your BMI and get insights into your body weight status.
Enter your details and click “Calculate” to see your results.
Select Units
Metric Units
Imperial Units
Your Input:
Gender: Male / Female
Height: 5 ft 10 in
Weight: 160 lbs
Your BMI Results:
BMI: 23 kg/m² (Healthy Weight)
BMI Category: Normal
Healthy BMI Range: 18.5 – 25 kg/m²
Recommended Weight for Height: 128.9 – 174.2 lbs
BMI Prime: 0.92
Ponderal Index: 12.9 kg/m³
What is BMI?
Body Mass Index (BMI) is a simple screening tool used to estimate a person’s body fat based on their height and weight. It’s commonly used to determine whether an individual falls within a healthy weight range. Although it doesn’t directly measure body fat, BMI provides a reliable indicator for most people and can highlight potential health risks.
Adult BMI Classification:
| Category | BMI Range (kg/m²) |
|---|---|
| Severely Underweight | Less than 16 |
| Underweight | 16 – 18.5 |
| Normal Weight | 18.5 – 25 |
| Overweight | 25 – 30 |
| Obese (Class I) | 30 – 35 |
| Obese (Class II) | 35 – 40 |
| Obese (Class III) | Over 40 |
Children’s BMI (Age 2–20):
For children and teens, BMI is interpreted using age- and sex-specific percentiles:
| Category | Percentile Range |
|---|---|
| Underweight | Below 5th |
| Healthy Weight | 5th – 85th |
| At Risk of Overweight | 85th – 95th |
| Overweight | Above 95th |
Health Risks of High BMI
Carrying excess weight can significantly raise your chances of developing:
High blood pressure and cholesterol
Type 2 diabetes
Heart disease and stroke
Joint problems like osteoarthritis
Breathing issues and sleep apnea
Certain cancers
Lower quality of life and mental health challenges
Increased risk of premature death
Health Risks of Low BMI
Being underweight can also have serious effects on your health:
Nutrient deficiencies and anemia
Weakened immunity
Bone loss and osteoporosis
Fertility and pregnancy complications
Developmental issues in children
Greater surgery-related risks
Higher mortality rates
Limitations of BMI
While BMI is a helpful general indicator, it doesn’t account for:
Muscle mass vs. fat mass
Age or gender differences
Ethnic and genetic factors
Athletic body types (e.g., athletes may have high BMI but low fat)
For more accurate health assessment, consider additional measures such as body fat percentage, waist circumference, and medical evaluations.
How BMI is Calculated
US Customary Formula:
BMI = (Weight in lbs ÷ Height in inches²) × 703
Example:
BMI = (160 ÷ 70²) × 703 = 23
Metric Formula:
BMI = Weight (kg) ÷ Height² (m)
Example:
BMI = 72.57 ÷ (1.778)² = 23
Understanding BMI Prime
BMI Prime shows how your BMI compares to the upper healthy limit (25).
Formula:
BMI Prime = BMI ÷ 25
| Classification | BMI Prime |
|---|---|
| Underweight | < 0.74 |
| Normal | 0.74 – 1 |
| Overweight | 1 – 1.2 |
| Obese | > 1.2 |
What is the Ponderal Index?
The Ponderal Index (PI) is another measure of body composition, particularly effective for very tall or short individuals. It uses height cubed instead of squared.
Formula (US Units):
PI = Height (in) ÷ ∛Weight (lbs)
Example:
PI = 70 ÷ ∛160 ≈ 12.9
The BMI Calculator provides a quick snapshot of your weight category and related health implications. It’s a helpful starting point, but it shouldn’t be the only measure you rely on. For understanding of your health, speak with a healthcare professional.
FAQs
1. What is BMI and why is it important?
Body Mass Index (BMI) is a simple calculation that uses your height and weight to estimate if you’re within a healthy weight range. It’s an effective screening tool to identify potential weight-related health risks, such as obesity or being underweight.
2. How is BMI calculated?
BMI is calculated using the formula:
For US Units:
BMI = (703 × weight in lbs) / (height in inches)²For Metric Units:
BMI = weight in kg / (height in meters)²
You can easily calculate it by entering your height and weight in the calculator above.
3. What does my BMI result mean?
Your BMI result places you in a category:
Underweight: BMI below 18.5
Normal weight: BMI between 18.5 and 24.9
Overweight: BMI between 25 and 29.9
Obese: BMI 30 or higher
These ranges help assess your potential health risks related to body weight.
4. Does age or gender affect BMI?
While BMI itself doesn’t directly account for age or gender, our calculator factors in your age and gender for a more personalized result. In general, men and women have different body compositions, and age can influence body fat distribution.
5. Is BMI an accurate measure of health?
BMI is a useful general indicator, but it has limitations. It doesn’t distinguish between muscle and fat, so athletes may have a high BMI despite low body fat. It’s best used alongside other health metrics, like waist circumference, activity level, and overall fitness.
6. What is BMI Prime?
BMI Prime is a ratio of your BMI to the upper limit of the normal BMI range (25). A BMI Prime of 1 or lower means you’re within a healthy range. Values above 1 suggest excess weight, while below 0.74 indicate underweight status.
7. What is the Ponderal Index (PI)?
The Ponderal Index is another measure of body composition, better suited for very short or tall individuals. It uses your height cubed instead of squared, which helps reduce inaccuracies in those with extreme body types.
8. What is a healthy BMI range for adults?
According to global health guidelines, a BMI between 18.5 and 24.9 kg/m² is considered healthy for most adults. However, ideal ranges can differ slightly depending on ethnicity, age, and fitness levels.
9. Can children and teens use this calculator?
This calculator is primarily designed for adults. BMI interpretation for children and teens is based on age- and sex-specific percentiles rather than fixed ranges. Parents should consult a pediatrician for accurate assessments.
10. What health risks are associated with a high BMI?
A high BMI can increase the risk of:
Heart disease
Type 2 diabetes
High blood pressure
Joint issues
Certain cancers
Sleep disorders
Maintaining a healthy weight can significantly reduce these risks.
11. What if my BMI is below the healthy range?
Being underweight can lead to problems like weakened immunity, nutrient deficiencies, and hormonal issues. If your BMI is too low, consult a healthcare provider to determine the underlying cause and appropriate actions.
12. How can I use my BMI results to improve my health?
BMI can be a helpful starting point for setting goals. If you’re outside the healthy range, consider speaking with a doctor or dietitian about lifestyle changes such as improving your diet, increasing physical activity, or addressing underlying medical conditions.