BMI Calculator
- Healthy BMI range: 18.5 kg/m² - 25 kg/m²
- Healthy weight for the height: ---
- BMI Prime: ---
- Ponderal Index: --- kg/m³
A BMI calculator is a tool that estimates body fat based on height and weight. It works by dividing your weight in kilograms by your height in meters squared. The result places you in a weight category such as underweight, normal, overweight, or obese. This simple calculation helps you understand if your body weight falls within a healthy range for your height.
The main benefits of using a BMI calculator include early detection of weight-related health risks, weight management tracking, and monitoring body fat levels. It serves as a screening tool for identifying potential health issues like heart disease, diabetes, and high blood pressure before they become serious.
People use BMI calculators for several purposes: assessing their current health status, setting weight loss or gain goals, tracking progress over time, and providing data for health insurance applications. Healthcare professionals also use BMI as one indicator among many when evaluating patient health.
A standard BMI calculator has a few key parts: height input field, weight input field, calculation algorithm, and result display showing your BMI number and weight category. Some advanced calculators include age, gender, and ethnicity adjustments for more accurate results.
What to Know
Body mass index (BMI) is a calculated measure of weight relative to height. For adults, BMI is categorized into underweight, healthy weight, overweight, and obesity. Obesity is further subdivided into three classes. This BMI calculator is for adults 20 and older.
BMI is one potential health indicator and should be considered with other factors when assessing an individual's health. These factors may include a patient's medical history, health behaviors, physical exam findings, and laboratory findings. Persons may consider seeking advice from their health care providers about their BMI. This calculator is not a substitute for professional medical advice.
Units
The calculator supports three unit systems:
- US units: feet/inches for height, pounds for weight
- Metric units: centimeters or meters for height, kilograms for weight
- Other units: stones for weight, inches for height
Calculated Results
When you enter your data, the calculator provides:
- Your BMI value (e.g., 23 kg/m²)
- Your weight category (underweight, normal, overweight, obese)
- Healthy BMI range (18.5 - 24.9 kg/m²)
- Healthy weight for your height
- BMI Prime value
- Ponderal Index value
Who Should Not Use This Tool
You should not use this BMI calculator if you:
- Are under 18 years old
- Are pregnant
- Have been diagnosed with an eating disorder
- Have a condition that affects your height
For children and teens aged 2 through 19 years, use the BMI Calculator for Children and Teens.
What You Will Need
To use the calculator, you will need to know your:
- Height
- Weight
Some calculators also ask for your age, gender, and ethnic background. This is because people from Asian, Black African, African-Caribbean, or Middle Eastern ethnic backgrounds have a higher chance of developing health problems at a lower BMI.
What Your Result Means
Your BMI result will be displayed as a number with one of these weight categories:
A higher BMI increases the chance of developing long-term conditions, such as type 2 diabetes and heart disease. The BMI calculation is just one measure of health. It cannot tell the difference between muscle and fat. After getting your result, you may be asked to measure your waist to understand if you are carrying too much weight around your tummy.
BMI
BMI Introduction
BMI is a measurement of a person's leanness or corpulence based on their height and weight, and is intended to quantify tissue mass. It is widely used as a general indicator of whether a person has a healthy body weight for their height. Specifically, the value obtained from the calculation of BMI is used to categorize whether a person is underweight, normal weight, overweight, or obese depending on what range the value falls between.
These ranges of BMI vary based on factors such as region and age, and are sometimes further divided into subcategories such as severely underweight or very severely obese. Being overweight or underweight can have significant health effects, so while BMI is an imperfect measure of healthy body weight, it is a useful indicator of whether any additional testing or action is required.
BMI Table for Adults
This is the World Health Organization's (WHO) recommended body weight based on BMI values for adults. It is used for both men and women, age 20 or older.
| 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 |
BMI Chart for Adults
The BMI chart for adults is a graph of BMI categories based on World Health Organization data. The colors represent the major BMI categories, and the gray contour lines represent integer BMI values for different height–weight combinations.
BMI Table for Children and Teens, Age 2-20
The Centers for Disease Control and Prevention (CDC) recommends BMI categorization for children and teens between age 2 and 20.
| Category | Percentile Range |
|---|---|
| Underweight | < 5% |
| Healthy weight | 5% - 85% |
| At risk of overweight | 85% - 95% |
| Overweight | > 95% |
BMI Chart for Children and Teens, Age 2-20
The CDC provides BMI-for-age percentiles growth charts for boys and girls separately.
Risks Associated with Being Overweight
Being overweight increases the risk of a number of serious diseases and health conditions. According to the Centers for Disease Control and Prevention (CDC), these include:
- High blood pressure
- Higher levels of LDL cholesterol and lower levels of HDL cholesterol
- Type II diabetes
- Coronary heart disease
- Stroke
- Gallbladder disease
- Osteoarthritis
- Sleep apnea and breathing problems
- Certain cancers (endometrial, breast, colon, kidney, gallbladder, liver)
- Low quality of life
- Mental illnesses such as clinical depression and anxiety
- Body pains and difficulty with physical functions
- Increased risk of mortality
A person should try to maintain a BMI below 25 kg/m², but should consult their doctor to determine if they need to make lifestyle changes.
Risks Associated with Being Underweight
Being underweight has its own associated risks:
- Malnutrition, vitamin deficiencies, anemia
- Osteoporosis
- Decreased immune function
- Growth and development issues in children and teenagers
- Reproductive issues for women, including higher chance of miscarriage
- Complications from surgery
- Increased risk of mortality
In some cases, being underweight can be a sign of an underlying condition such as anorexia nervosa.
Limitations of BMI
BMI is only an estimate that cannot take body composition into account. Due to a wide variety of body types as well as distribution of muscle, bone mass, and fat, BMI should be considered along with other measurements.
In adults:
- Older adults tend to have more body fat than younger adults with the same BMI
- Women tend to have more body fat than men for an equivalent BMI
- Muscular individuals and athletes may have higher BMIs due to large muscle mass
In children and adolescents:
- Height and level of sexual maturation can influence BMI
- BMI is a better indicator of excess body fat for obese children than overweight children
- In thin children, BMI differences can be due to fat-free mass
BMI is fairly indicative of body fat for 90-95% of the population and can effectively be used along with other measures.
BMI Formula
US Customary Units:
BMI = 703 × mass (lbs) / height² (in) Example for a 5'10", 160-pound person:
BMI = 703 × 160 / 70² = 23.0
SI Metric Units:
BMI = mass (kg) / height² (m) Example for a 72.57 kg, 1.778 m person:
BMI = 72.57 / 1.778² = 23.0
BMI Prime
BMI prime is the ratio of a person's measured BMI to the upper limit of BMI considered normal (25 kg/m²).
BMI prime = BMI / 25 | Classification | BMI | BMI Prime |
|---|---|---|
| Severe Thinness | < 16 | < 0.64 |
| Moderate Thinness | 16 - 17 | 0.64 - 0.68 |
| Mild Thinness | 17 - 18.5 | 0.68 - 0.74 |
| Normal | 18.5 - 25 | 0.74 - 1 |
| Overweight | 25 - 30 | 1 - 1.2 |
| Obese Class I | 30 - 35 | 1.2 - 1.4 |
| Obese Class II | 35 - 40 | 1.4 - 1.6 |
| Obese Class III | > 40 | > 1.6 |
BMI prime allows quick assessment of how much a person's BMI differs from the normal upper limit.
Ponderal Index
The Ponderal Index (PI) is similar to BMI but cubes height instead of squaring it. PI is more reliable for very tall or short individuals.
US Customary Units:
PI = height (in) / ∛mass (lbs) SI Metric Units:
PI = mass (kg) / height³ (m) Exercise Target Heart Rate Range Calculator
An Exercise Target Heart Rate Range Calculator helps you determine the ideal heart rate zone for effective and safe exercise. This tool uses your age and resting heart rate to calculate your target heart rate range for moderate and vigorous physical activity.
18.5 - 24.9
This is the healthy BMI range for adults. A BMI between 18.5 and 24.9 indicates a normal weight status with lower risk of weight-related health problems.
0 - 0 Kg
This is the healthy weight range for your height. The calculator displays the weight range that corresponds to a healthy BMI for your specific height.
Lose 0 Kg
The calculator shows how much weight you need to lose or gain to reach a healthy BMI range.
All Fields Are Mandatory
All input fields in the BMI calculator must be filled in to get accurate results. Missing information will prevent the calculation from completing.
What Is BMI?
Body Mass Index or BMI is an estimate of a person's leanness or body fat based on their body weight and height. It is designed to assess tissue mass and is commonly used as a general measure of whether a person's body weight is appropriate for their height.
Specifically, the result derived from the BMI calculation is used to determine whether a person is underweight, normal weight, overweight, or obese. These BMI values vary depending on geography and age. Although BMI is not a perfect estimate of healthy body weight, it may be a helpful tool in determining if further testing or treatment is necessary.
BMI Chart Highlights
A BMI chart displays BMI values across different heights and weights. The chart shows weight categories using color coding:
< 18.5
18.5 - 24.9
25 - 29.9
30 - 35
> 35
What Is a BMI Calculator?
The Body Mass Index calculator or BMI calculator is a useful tool that determines your current weight status. It takes into account both height and weight to give a better idea of your health status. BMI also considers age factors while calculating.
When analyzing applications for life insurance and health insurance, BMI is taken into account to understand health condition and propose appropriate premium amounts.
How to Calculate BMI?
A step-by-step calculation of body mass index requires accurate measurement of height and weight.
Multiply your height by itself (H × H)
Divide weight by the answer from step 1 (W / H²)
International System of Units
BMI = weight (kg) / height² (m²) Example: A man who is 1.5 meters tall and weighs 72 kg:
BMI = 72 / (1.5)² = 72 / 2.25 = 32
Imperial System
BMI = 703 × [weight (lbs) / height² (inches²)] Example: A woman who is 5'2" (62 inches) and weighs 145 pounds:
BMI = 703 × [145 / (62 × 62)] = 703 × [145 / 3844] = 26.5
How to Use the BMI Calculator?
The calculator will give:
BMI Ranges
There are five basic BMI ranges:
- Underweight: Less than 18.5
- Normal weight: 18.5 - 24.9
- Overweight: 25 - 29.9
- Obesity: 30 - 35
- Severe obesity: 35 above
BMI for Men
| BMI Range | Weight Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 - 24.9 | Healthy |
| 25 - 29.9 | Overweight |
| 30 - 35 | Obese |
| Above 35 | Morbid Obesity |
For men above age 20, the ideal BMI ranges from 18.5 to 24.9.
BMI for Children & Teenagers (5 – 18 Years)
Body fat of children changes rapidly as they grow. BMI for children is adjusted using percentiles rather than fixed numbers. In India, BMI for children aged 5-18 years uses adult equivalent cut-off lines of 23 and 27. BMI percentiles for children and teenagers are different for boys and girls.
Why Use a BMI Calculator?
Monitor Body Fat
Monitoring body fat is essential to understand risks associated with being overweight and underweight. The right amount of body fat helps the body utilize vitamins and minerals, providing optimal energy.
Prevent Health Conditions Later in Life
Healthcare professionals use a body mass index calculator to diagnose lifestyle-related health issues associated with weight. It classifies weight types by BMI ranges.
Weight Management
Calculating your actual weight through BMI helps you set realistic goals for a healthier weight. You can set an effective weight management strategy.
Height-to-Weight Ratio
The body mass index calculator helps you analyze your weight in accordance with your height. BMI accounts for height to provide more accurate weight estimates.
Early Detection of Serious Health Risks
Studies suggest a strong link between high BMI and certain cancers and type 2 diabetes. BMI calculator helps in keeping track of your weight and maintaining it within limits.
Importance of a BMI Calculator
BMI calculator plays a vital role in checking whether a person is healthy. It is an easy-to-use tool for assessing health and works as an obesity indicator.
- Assessing body weight and health risks: Physicians can get an idea of current health status and create better treatment plans
- Managing body weight: Useful for managing how much weight to lose or gain
- Public health assessment: BMI calculators help prepare national health-related data
- Determining insurance premium: Insurance companies use BMI to determine health risk and premium amounts
- Weight tracking: Beneficial for weight watchers during their weight loss or gain journey
What Are the Risks of Being Overweight?
A BMI score of 25 or higher indicates overweight. Risks include:
- Type 2 diabetes and insulin resistance
- Heart disease and stroke
- High blood pressure
- Certain cancers
- Digestive issues
- Sleep apnea
- Osteoarthritis
- Fatty liver disease
- Breathing trouble
- Hernia
- Varicose veins
- Cataract
- Gout
- Stress incontinence
- Mental health issues
- PCOS in women
- Menstrual cycle irregularities
What Are the Risks of Being Underweight?
A BMI score of 18.5 or less indicates underweight. Risks include:
- Osteoporosis
- Thinning skin, hair loss, dry skin
- Poor dental health
- Frequent illness
- Fatigue
- Anemia
- Irregular menstrual cycle
- Premature delivery
- Slow growth
Is BMI Reliable?
The body mass index calculator is an essential tool for checking weight and assessing certain health conditions. Although it can be used as a general health indicator, it cannot be used as a diagnostic tool. Healthcare providers use BMI alongside blood tests, screening, and imaging to accurately rule out health issues.
Health conditions depend on genetics and environmental factors in addition to body mass index. Visit a professional healthcare provider for an accurate diagnosis.
What Are the Steps to Maintain Optimum Health?
Diet
Natural foods instead of processed.
Exercise
Regular movement lowers risk.
Hydration
3 to 4 liters of water daily.
Sleep
7 to 8 hours for recovery.
Also track heart health regularly and practice good hygiene (handwashing/sanitizing).
Limitations of an Online BMI Calculator
No Male-Female Division
BMI doesn't account for different body fat levels between males and females necessary for optimal physical and mental functioning.
No Difference Between Muscle and Fat
BMI cannot distinguish between body fat and muscle. A person with high muscle mass may have a high BMI despite low body fat.
BMI Limitation for Children
A child's BMI can fluctuate significantly due to ongoing changes in height and weight. An active child may show as underweight, giving false indication of poor health. BMI also does not consider ethnicity and race. Asians generally have up to 5% more body fat than Caucasians.
Alternate Estimates of Weight-Related Health Risks
Waist Circumference
Measures fat deposited in the abdomen. A waist circumference of 35 inches and above in women and 40 inches and above in men indicates higher abdominal fat.
Waist-to-Hip Ratio (WHR)
Calculated by dividing waist measurement by hip measurement. A WHR of 0.86 or higher in women and 1.0 or higher in men indicates high health risks.
Skinfold Thickness
Provides analysis of fat beneath the skin at different body sites. Measured using a special caliper at locations such as trunk, thighs, and back.
Ponderal Index
Ponderal Index is another way of measuring health, similar to BMI. However, PI gives more accurate results by including the cubic power of height. The formula is weight/height³.
PI for adults uses kilograms for weight and meters for height. For children, it uses grams and centimeters.
Ponderal Index Formula
PI formula for infants: (Birth weight (g) × 100) / (Crown heel length (cm))³
PI formula for adults: Weight (kg) / (Height (m))³
| Category | Range |
|---|---|
| Severe Underweight | < 8 |
| Underweight | 8 - 11 |
| Normal | 11 - 15 |
| Overweight | 15 - 17 |
| Obese | ≥ 17 |
Does BMI Affect Your Health Insurance Premium?
BMI has a crucial role in determining your health insurance premium. Insurance companies use a BMI calculator to assess health risk.
Individuals with Higher BMI
Higher BMI above 24.9 increases risk of diabetes, cardiac issues, and hypertension. Insurance companies charge higher premiums due to increased claim frequency.
Individuals with Lower BMI
BMI below 18.5 increases risk of malnutrition-related health issues. Insurance companies charge higher premiums for such policyholders.
Individuals with Healthy BMI
Those with BMI between 18.5 and 24.9 can negotiate for lower premiums or discounts. Low-risk profile means lower insurance charges.
FAQs About BMI Calculator
Can results of BMI calculator vary for the same person over time?
Yes. Factors used for BMI calculator such as weight, hip size, and waist size change over time and lead to different results.
Can the BMI calculator serve as a way to diagnose my medical condition?
No. While BMI calculator can help estimate body fat, it cannot diagnose medical problems.
What can lead to high BMI?
A sedentary lifestyle with limited exercise and poor food habits can lead to high BMI. Genetics can also play a role.
Does the high result of BMI Calculator mean anything?
Low BMI individuals are prone to deficiencies and deficiency-related disorders. Take heed if the BMI calculator indicates underweight.
How to perform a BMI check?
BMI = weight (kg) / height² (m²). Example: 70 kg ÷ (1.75 × 1.75) ≈ 22.9
Can BMI be used during pregnancy?
Body mass index can be used in early pregnancy but can be misleading during pregnancy due to expected weight changes.
How do I calculate my BMI?
Divide your weight by the square of your height using metric units.
Is a BMI of 20 a lot?
No. A BMI score of 20 falls within the normal weight range of 18.5-24.9.
What is the ideal BMI range?
For young and middle-aged adults, the ideal BMI range is 18.5 to 24.9.
How is BMI measured?
Body mass index is measured by dividing weight in kilograms by height in meters squared.
What is the ideal BMI for a man?
The ideal body mass index for men is between 18.5 and 24.9.
What is the ideal BMI for a woman?
The ideal body mass index for a woman falls within the range 18.5-24.9.
How much should I weigh for my height and age?
A body mass index between 18.5 and 24.9 is considered a healthy weight range.
What is the purpose of calculating BMI?
Body mass index is a quick tool to estimate body fat and assess health conditions such as heart disease, diabetes, and blood pressure.
Are there any age- or gender-specific considerations for BMI?
Body mass index does not account for differences in health charts across age groups or genders. This is a major disadvantage.
Should I ignore my weight and concentrate on my BMI?
No. BMI does not capture differences in body composition and fat distribution, which could yield inaccurate results.
References
- Centers for Disease Control and Prevention (CDC)
- World Health Organization (WHO)
- National Heart, Lung, and Blood Institute (NHLBI)
- Singapore Heart Foundation
- Axis Max Life Insurance
More information to support a heart-healthy lifestyle
- Maintain a healthy weight
- Eat a heart-healthy diet
- Prepare healthy recipes
- Increase physical activity