Use our free BMI Calculator to calculate your Body Mass Index (BMI) online. Enter your weight in kilograms (kg) or pounds (lb) and height in centimeters (cm) or feet (ft) to calculate your BMI, find your BMI category, and see the estimated healthy weight range.
BMI Calculator
Calculate your Body Mass Index using your weight and height.
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What Is BMI?
BMI stands for Body Mass Index. It is a commonly used screening measurement based on a person's weight and height.
BMI can help categorize a person's weight into different ranges, such as underweight, normal weight, overweight, and obesity.
The BMI calculation uses weight and height and does not directly measure body fat, muscle mass, or overall health.
How to Calculate BMI
The standard BMI formula is:
BMI = Weight (kg) ÷ Height² (m)
For example, if a person's weight is 70 kg and height is 1.70 meters:
BMI = 70 ÷ (1.70 × 1.70)
BMI = 24.2
The BMI Calculator above performs this calculation automatically.
You do not need to manually convert pounds or feet into kilograms and meters because the calculator supports both kg/lb and cm/ft.
BMI Categories for Adults
The commonly used adult BMI categories are:
| BMI Range | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 or higher | Obesity |
These categories are intended as general screening ranges for adults. BMI should not be considered a complete assessment of an individual's health.
Healthy BMI Range
For adults, a BMI between 18.5 and 24.9 is commonly considered the healthy or normal BMI range.
The healthy weight corresponding to this range depends on a person's height.
Our calculator estimates the weight range corresponding to a BMI of 18.5 to 24.9 based on the height you enter.
BMI Calculator in kg
If you know your weight in kilograms, select kg from the weight unit option.
For example:
- Weight: 70 kg
- Height: 170 cm
- BMI: approximately 24.2
The calculator automatically converts the height into meters and calculates the BMI.
BMI Calculator in Pounds
You can also calculate BMI using weight in pounds (lb).
Select lb from the weight unit option and enter your weight.
For example:
- Weight: 154 lb
- Height: 170 cm
The calculator automatically converts pounds into kilograms before calculating BMI.
BMI Calculator Using cm
If your height is available in centimeters, select cm and enter your height.
For example:
170 cm
The calculator converts the height into meters for the BMI calculation.
BMI Calculator Using Feet
If you know your height in feet, select ft and enter the height as a decimal value.
For example:
5.58 ft
This is approximately equivalent to 5 feet 7 inches.
The calculator automatically converts the height into meters before calculating BMI.
How to Use the BMI Calculator
Follow these simple steps:
- Enter your weight.
- Select kg or lb.
- Enter your height.
- Select cm or ft.
- Click Calculate BMI.
- Your BMI value and BMI category will be displayed.
- The calculator also shows the standard healthy BMI range and an estimated healthy weight range.
To start again, click the Reset button.
BMI Formula
The BMI formula is:
BMI = Weight in kilograms ÷ Height in meters²
For example:
Weight = 70 kg
Height = 1.70 m
Therefore:
BMI = 70 ÷ (1.70 × 1.70)
BMI = 24.2
The same calculation can be performed when weight is given in pounds or height is given in feet after converting the measurements to kilograms and meters.
Is BMI an Accurate Measure of Health?
BMI is a useful screening measurement, but it does not provide a complete picture of a person's health.
BMI does not directly distinguish between:
- Muscle and fat
- Bone mass
- Fat distribution
- Different body compositions
For example, a person with a high amount of muscle may have a higher BMI even though they have relatively low body fat.
Therefore, BMI should be interpreted together with other relevant health and body measurements when appropriate.
Who Should Not Use Adult BMI Categories?
The standard adult BMI categories are not intended to be a complete assessment for everyone.
BMI interpretation can differ for:
- Children
- Teenagers
- Pregnant people
- Some athletes
- People with unusually high muscle mass
For children and teenagers, BMI is generally interpreted using age- and sex-specific growth references rather than the standard adult categories.
BMI Calculator – Frequently Asked Questions
What is a BMI Calculator?
A BMI Calculator is an online tool that calculates Body Mass Index using a person's weight and height. It can also show the corresponding BMI category.
What is the normal BMI range?
For adults, a BMI of 18.5 to 24.9 is commonly classified as the normal or healthy BMI range.
Can I calculate BMI using pounds?
Yes. This BMI Calculator allows you to enter weight in pounds (lb). The calculator automatically converts the value before calculating BMI.
Can I calculate BMI using feet?
Yes. Select ft as the height unit and enter your height as a decimal value, such as 5.58 ft.
Can I use centimeters for height?
Yes. Select cm and enter your height in centimeters, such as 170 cm.
What BMI is considered overweight?
For adults, a BMI from 25.0 to 29.9 is commonly classified as overweight.
What BMI is considered obesity?
For adults, a BMI of 30.0 or higher is commonly classified within the obesity range.
How is BMI calculated?
BMI is calculated by dividing weight in kilograms by height in meters squared.
BMI = Weight (kg) ÷ Height² (m)
Is BMI the same for men and women?
The standard adult BMI calculation uses the same formula for men and women. However, BMI does not account for differences in body composition, so it should not be interpreted as a complete measure of health.
Does BMI measure body fat?
No. BMI is calculated from weight and height and does not directly measure body fat.
BMI Calculator Summary
Our free BMI Calculator makes it easy to calculate Body Mass Index using different measurement units. You can enter:
- Weight in kg or lb
- Height in cm or ft
The calculator provides your BMI value, BMI category, standard healthy BMI range, and an estimated healthy weight range based on your height.
Use the calculator above whenever you need a quick BMI calculation online.
Important: BMI is a general screening measure and should not be treated as a diagnosis or a substitute for professional medical advice.
