BMI Calculator (kg, lbs) + BMI Chart Explained

 Body Mass Index (BMI) is a simple way to check whether your weight is healthy for your height. It is commonly used by doctors, fitness professionals, and individuals to get a quick overview of body weight status.

BMI Calculator

Choose Unit:
kg & cm lbs & inches

Weight:


Height:

BMI Range	Weight Category
Below 18.5	Underweight
18.5 – 24.9	Normal weight
25.0 – 29.9	Overweight
30.0 and above	Obese

BMI or Body Mass Index is a simple number that shows whether your weight is in a healthy range for your height. It’s one of the easiest ways to check if you're underweight, normal weight, overweight, or obese.

Doctors and fitness apps use BMI as a quick screening tool. It’s not perfect, but it gives you a useful starting point to understand your body weight.

 

BMI Formula (kg and lbs)

There are two versions of the formula depending on which units you use.

1. Metric Formula (kg and cm)

If your height is in meters:

BMI = Weight (kg) ÷ Height² (m²)

If your height is in centimeters:

BMI = Weight (kg) ÷ (Height (cm) ÷ 100)²

Example (Metric)

Weight = 60 kg
Height = 160 cm (1.60 m)

BMI = 60 ÷ (1.60 × 1.60)
BMI = 60 ÷ 2.56
BMI = 23.44

This is considered normal weight.

2. Imperial Formula (lbs and inches)

If you use pounds and inches:

BMI = (Weight (lbs) ÷ Height² (inches²)) × 703

Example (Imperial)

Weight = 132 lbs
Height = 63 inches

BMI = (132 ÷ 3969) × 703
BMI = 0.0333 × 703
BMI = 23.41

 

BMI Chart Explained

Once you get your BMI number, you can compare it with the chart below:

BMI	Category
Below 18.5	Underweight
18.5 – 24.9	Normal weight
25.0 – 29.9	Overweight
30.0 – 34.9	Obese (Class I)
35.0 – 39.9	Obese (Class II)
40.0+	Obese (Class III)

In simple terms:

• Under 18.5 → You may need to gain weight
• 18.5–24.9 → Healthy range
• 25–29.9 → Slightly above healthy range
• 30+ → Higher health risk

 

How to Calculate BMI (Step‑by‑Step)

Metric

1. Measure your weight in kilograms
2. Measure your height in centimeters
3. Convert height to meters (divide by 100)
4. Multiply height by itself
5. Divide weight by that number

Imperial

1. Measure your weight in pounds
2. Measure your height in inches
3. Multiply height by itself
4. Divide weight by that number
5. Multiply the result by 703

 

Example BMI Calculations

Example 1

Height: 153 cm
Weight: 60 kg

BMI = 60 ÷ (1.53 × 1.53)
BMI = 25.63

Category: Overweight

 

Example 2

Height: 170 cm
Weight: 65 kg

BMI = 65 ÷ (1.70 × 1.70)
BMI = 22.49

Category: Normal weight

 

Why BMI is Useful

BMI helps you quickly understand if your weight might increase your risk for health problems such as heart disease, diabetes, high blood pressure, joint stress and many more. It also commonly used in health apps, clinics, and fitness programs.

 

But it is important to remember that, BMI is helpful, but it doesn’t tell the full story. It won’t know how much is your weight muscle, fat or even body shape. Therefore, Just remember — BMI is only a general guide. Your overall health depends on many things, including body fat, lifestyle, and medical factors.