BMI Calculator

Age

Gender

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Height

feet

inches

Weight

pounds

BMI = -- kg/m

Healthy BMI Range: 18.5 - 25 kg/m
Healthy weight for your height:

BMI Calculator

This BMI Calculator was designed to calculate the Body Mass Index (BMI) based on a user’s input for Age, Gender, weight and height.

It included options for both metric (kg, cm) and US units (lbs, inches). The calculator displayed the resulting BMI value and categorized it into ranges such as underweight, normal weight, overweight, and obesity. Additionally, it provided health advice based on the BMI category and displayed an ideal weight range for the user’s height. The interface was clear and user-friendly, with a visual gauge representing the BMI value on a scale.

What is BMI?

BMI, or Body Mass Index, is a numerical value derived from an individual’s weight and height. It is commonly used as a screening tool to categorize people into different weight status categories and to assess potential health risks related to weight. BMI does not measure body fat directly, but it provides an estimate based on weight-to-height ratio.

How to Calculate BMI?

1. Metric Units (kg and meters)

Formula:

$\text{BMI}=\frac{\text{Weight(kg)}}{\text{Height(m)}^2}$

Example:

Weight = 70 kg
Height = 1.75 meters

Calculation:

$\text{BMI}=\frac{70\,\text{kg}}{(1.75\,\text{m})^2}=\frac{70\,\text{kg}}{3.0625\,\text{m}^2}\approx 22.86\,\text{kg/m}^2$

So, the BMI is approximately 22.86, which falls in the “Normal weight” category according to the WHO classification.

2. Imperial Units (pounds and inches)

Formula:

$\text{BMI}=\frac{\text{Weight(lbs)}}{\text{Height(in)}^2}\times 703$

Example:

Weight = 154 lbs
Height = 69 inches

Calculation:

$\text{BMI}=\frac{154\,\text{lbs}}{(69\,\text{in})^2}\times 703=\frac{154\,\text{lbs}}{4761\,\text{in}^2}\times 703\approx 22.77$

So, the BMI is approximately 22.77, which also falls in the “Normal weight” category.

BMI table for adults

This table applies World Health Organization's (WHO) BMI values and classifications, to visually categorize weight status and related health risks, it's suitable for both men and women, aged 20 or older.

Classification	BMI Range (kg/m²)	Health Risk Description
Severe Thinness	< 16	Extremely high risk of malnutrition, weakened immunity
Moderate Thinness	16–17	Increased risk of nutrient deficiencies
Mild Thinness	17–18.5	Potential health risks; dietary monitoring advised
Normal	18.5–25	Lowest health risks associated with this range
Overweight	25–30	Elevated risk of cardiovascular diseases
Obese Class I	30–35	Significantly increased metabolic risks
Obese Class II	35–40	High risk requiring medical intervention
Obese Class III	≥ 40	Extremely high risk of severe complications

Limitations:

While BMI is a useful tool for identifying potential health risks associated with being underweight, overweight, or obese, it does not account for factors such as:

Muscle mass: Athletes or individuals with high muscle mass may have a high BMI, but not have excessive body fat.
Distribution of fat: BMI doesn’t distinguish between fat stored in different parts of the body (e.g., abdominal fat vs. thigh fat).

Despite these limitations, BMI remains a widely used and practical method for assessing weight-related health risks at a population level. It is often used by healthcare professionals as an initial screening tool to identify individuals who may need further evaluation for health conditions associated with abnormal weight.