The Ultimate BMI Calculator

Advanced BMI & Health Calculator

Calculator

Progress Tracker

Metric (kg, cm)

Imperial (lbs, ft, in)

Age

Sex at Birth

Height (cm)

Weight (kg)

Ethnicity (Optional)

Your saved progress will appear here.

Ready to Take the Next Step?

Your result is a great starting point. For a personalized diet plan that fits your unique body and goals, connect with DietArch founder and Certified Nutritionist, Sara Ali.

Get Your Custom Diet Plan

Disclaimer: This calculator is for informational purposes only and is not a substitute for professional medical advice. Always consult a healthcare provider for a complete health assessment.

Body Mass Index (BMI)

Body Mass Index (BMI) is a health screening tool approved by the World Health Organization (WHO). It uses a simple formula to measure your weight in relation to your height, giving a single number that helps you check your weight status.

The calculation is your weight (in kilograms) divided by the square of your height (in meters).

Health professionals use BMI because it is a reliable indicator of body fatness for most people. It is trusted all over the world as it is strongly linked with the risk for certain health conditions. It is a quick and effective way to assess your health from a broad perspective.

Calculate your macronutrient split with our macro calculator.

What does BMI tell you?

BMI is a simplest way to check if your weight is healthy for your height. It gives you a number that falls into a category:

BMI Range	Category
Below 16	Severely underweight
16 – 17	Moderately underweight
17 – 18.5	Slightly underweight
18.5 – 25	Normal (Healthy)
25 – 30	Overweight
30 – 35	Obesity Class 1
35 – 40	Obesity Class 2
Above 40	Obesity Class 3

Example:

Age: 25
Height: 5 feet 10 inches
Weight: 160 lbs
BMI: 23 — This falls in the “Normal” or healthy weight range.

A healthy BMI is between 18.5 and 25. For a person who is 5’10”, a healthy weight would be between about 129 and 174 pounds.

Check what should be your Ideal Body Weight.

BMI Table for Children and Teens (Ages 2–20)

For kids and teenagers, BMI works a bit differently than it does for adults. Instead of using fixed numbers, doctors look at percentiles based on age and gender.

Category	What It Means
Underweight	Below the 5th percentile – The child is too thin for their age and height.
Healthy weight	Between the 5th and 85th percentile – This is considered a healthy, normal weight.
At risk of overweight	Between the 85th and 95th percentile – The child may be gaining too much weight.
Overweight	Above the 95th percentile – The child is heavier than what’s healthy for their age and height.

This system helps doctors and parents track a child’s growth and make sure their weight is in a healthy range as they grow. Percentiles compare a child’s BMI to others of the same age and gender.

BMI chart for children and teens

BMI-for-age percentiles growth charts for Boys

BMI-for-age percentiles
growth charts boys. Dietarch

BMI-for-age percentiles growth charts for Girls

BMI-for-age percentiles
growth charts girls. Dietarch

BMI Charts for Adults

BMI (Body Mass Index) charts enable a person to check its health status. There are two types of charts.

Types of BMI Charts

If you weigh 245 lb or less, use the first chart.

If you weigh more than 250 lb, use the second chart.

Color on the BMI Chart mean

The shaded areas show if your BMI is:

In the healthy range

Overweight

Or in one of the obesity categories

Levels of obesity:

Class 1 obesity: BMI between 30 and 34.9

Class 2 Obesity: BMI between 35 and 39.9

Class 3 (Severe Obesity): BMI 40 or higher

Read the one habit to reduce visceral fat.

BMI chart: Weight of 95 to 245 lb

BMI chart: Weight of 250 to 400 lb

These charts are based on a BMI guide developed by the University of Vermont.

Why is BMI important?

BMI helps you know if your weight is suitable for your body. It is not completely perfect but it is good enough to make an estimation. If your Body Mass Index is too low or too high, it is better to take your health seriously.

Health Risks of Being Overweight

Carrying extra pounds can be a reason of serious health problems. According to health experts, being overweight puts extra burden on body and increases the chances of developing the following conditions:

High blood pressure, which increases stress on the heart and arteries
Unhealthy cholesterol levels, which causes higher “bad” LDL cholesterol and lower “good” HDL cholesterol, as well as high triglycerides
Type 2 diabetes, a condition that affects how your body process sugar
Heart disease and stroke, which are common causes of death worldwide
Gallbladder issues, including gallstones
Osteoarthritis, which causes joint pain and stiffness
Breathing problems, including sleep apnea, in which breathing stops and starts while you sleep
Certain types of cancer, such as breast, colon, kidney, liver, gallbladder, and uterine cancer
Decreased quality of life, such as an inability to move around or do daily tasks
And struggles with mental health, like depression and anxiety
Persistent pain and difficulty with activities
Reduced life expectancy because of increased chance of fatal illness

Reduce risk of stroke with these habits.

Health Risks of Being Underweight

While it is less talked about, being underweight can also affect your health in many serious ways. It means your body is not geining the right weight with the nutrients and energy it needs to function properly. Risks include:

Poor nutrition, which can cause serious deficiencies
Anemia, a condition where your blood has trouble carrying enough oxygen
Weakened bones (osteoporosis), which increases the risk of fractures
A weaker immune system with slow resistance to infections
Slow growth and development more observed in children and teens
Hormonal issues in women like PCOS
Higher chance of complications during or after surgery
Increased risk of early death which is similar to the risks from being overweight

Check other health tools and calculators for further health assessment.

Limitations of BMI:

Although BMI (Body Mass Index) is a common and useful tool for checking whether a person’s weight is in a healthy range. It does not completely explain health status. It’s just a rough estimate and does not show all factors that make up a person’s body composition.

For Adults: BMI will not distinguish between fat, muscle, bone, and water weight. Therefore, two individuals can have identical BMI but different body composition. Following are identical limitations of BMI:

Muscle vs. fat: Muscle is heavier than fat, so athletic or very active persons might have a high BMI but low body fat and great health.
Age and physical activity: An elderly person who doesn’t exercise can have a healthy BMI but still be carrying excess body fat. Another young, active individual of the same BMI could be considerably healthier with more muscle and less fat.
Gender variations: Women also generally have more body fat than men, even at equal BMI.
Ethnic origin: Muscle density and fat distribution in the body may differ between ethnic groups and thus influence how BMI accurately portrays health.

For Children and Adolescents: For increasing children, factors that extend beyond weight come into play. Growth phases, puberty, and development all influence body shape and composition.

For obese children, BMI can be a useful marker of excess fat.
For thin or mildly obese children, BMI can represent fat but also fat-free mass such as muscle, organs, and water.
Since growing children become taller or reach puberty at varying ages, BMI can change rapidly without always representing a health issue.

What else does the BMI calculator show?

Along with BMI, it may also show:

BMI Prime: A ratio of your BMI to the upper limit of the normal range.
Ponderal Index: Another way to assess body composition, especially for tall or short individuals.

Body Mass Index (BMI): Calculation Methods

BMI, or Body Mass Index, is a standardized method used to check whether a person weight is within a healthy range relative to their height. It applies across both metric and imperial systems.

BMI Calculation Formulas

Using US Customary Units (USC):
To calculate BMI with pounds and inches given the following formula is applied:

BMI = 703 × Weight (lb)
[Height (in)]²

Example:
For an individual who is 5 feet 10 inches (70 inches) tall and weighs 160 pounds:

BMI = 703 × 160 / 70² = 23

Using Metric Units (SI):

Using kilograms and meters, the calculation is:

BMI = Weight (kg)
[Height (m)]²

Example:

For an individual who weighs 72.57 kg and is 1.778 meters tall:

BMI = Weight (kg) / [Height (m)]²

BMI = 72.57 / 1.778² = 23

BMI Prime

BMI Prime is a ratio of individual’s BMI to top of range of BMI, and it is a range of healthy weight. It is usually defined as 25 kg/m² by institutions such as the WHO and CDC.

It is a unitless quantity and provides an instant reference to see how far an individual’s BMI is from the top end of the normal range.

Interpretation of BMI Prime Values:

BMI Prime	Weight Category
< 0.64	Severe Thinness
0.64 – 0.68	Moderate Thinness
0.68 – 0.74	Mild Thinness
0.74 – 1.00	Normal Weight
1.00 – 1.20	Overweight
1.20 – 1.40	Obesity Class I
1.40 – 1.60	Obesity Class II
> 1.60	Obesity Class III

Ponderal Index (PI)

The Ponderal Index also calculates body composition but is more accurate for height as it takes a cubed height value instead of squared. It is considered more suitable for individuals at the extreme ends of the height spectrum, where BMI may be less accurate.

PI Calculation Formulas

Using US Customary Units:

PI = Height (in)
∛Weight (lb)

Example:
For someone 70 inches tall and 160 pounds:

PI = 70
∛160 ≈ 12.9

Using Metric Units:

PI = Weight (kg)
[Height (m)]³

Example:

PI = 72.57
1.778³ ≈ 12.9

Frequently Asked Questions

A healthy BMI varies by age. According to international health guidelines, the ideal range for adults aged 20-64 is 18.5-24.9. For older adults aged 65+, our calculator takes a slightly higher range as studies indicate this can be beneficial.

Yes. Because BMI does not differentiate between muscle and fat, people with high muscle mass (such as athletes) may have a BMI in the “Overweight” category yet be perfectly healthy.

This calculator is very accurate since its formulas and categories were directly based on the World Health Organization (WHO) and CDC standards published.

We have a voluntary ethnicity selection based on strong recommendations by the WHO. Research spanning decades indicates that individuals of Asian descent tend to have increased health risks at lower levels of BMI.

Body Mass Index: Calculate your BMI | Charts Complete Guide

The Ultimate BMI Calculator