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BMI Calculator – Body Mass Index

Understand Your Body Weight Category and Health Range

Body Mass Index (BMI) is a widely used screening tool that helps estimate whether a person’s body weight falls within a healthy range for their height. This BMI Calculator allows you to calculate your BMI quickly and understand what the result means for your overall health.

This tool is designed for educational and informational purposes and helps users worldwide better understand weight categories using internationally recognized standards.

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What Is BMI (Body Mass Index)?

BMI, or Body Mass Index, is a numerical value calculated using a person’s height and weight. It provides a simple way to categorize weight status and identify potential health risks related to underweight or excess body weight.

BMI is commonly used by:
  • Healthcare professionals
  • Public health organizations
  • Fitness and wellness programs

It is not a diagnostic tool, but rather a general indicator.

How to Use This BMI Calculator

Using this calculator is simple and requires no registration or personal data.

1

Step 1: Enter Your Age

BMI interpretation applies to adults. This calculator is intended for individuals within the specified age range.

2

Step 2: Select Gender

Gender is optional for calculation but may be used for result interpretation and future insights.

3

Step 3: Enter Height

Provide your height using either feet and inches (US units) or centimeters (metric units).

4

Step 4: Enter Weight

Input your current body weight in pounds or kilograms.

5

Step 5: Calculate

Click Calculate to instantly see your BMI value and category.

What Your BMI Result Tells You

Underweight

May indicate insufficient body weight, which can be associated with nutritional deficiencies or other health concerns.

Normal Weight

Generally associated with the lowest health risk for most adults.

Overweight

May increase the risk of certain health conditions, especially when combined with other lifestyle factors.

Obesity

Associated with higher risk for several chronic health conditions and may warrant medical guidance.

Important Health Considerations

BMI Is a Screening Tool

BMI does not measure body fat directly. It does not distinguish between muscle and fat, bone density differences, or fat distribution. Athletes and very muscular individuals may have a high BMI without excess body fat.

BMI Does Not Consider Overall Health

Factors such as diet quality, physical activity, genetics, and metabolic health are not included in BMI calculations.

BMI and Global Health Use

BMI is used worldwide because it is simple, non-invasive, cost-effective, and useful for population-level screening. However, individual health assessments should always go beyond BMI alone.

How BMI Is Calculated

The standard BMI formula is:

BMI = weight (kg) ÷ height² (m²)

For users entering values in US units, weight and height are converted into metric units internally before calculation.

The calculator automatically handles these conversions so you can enter values in either metric or US units.

Example BMI Calculation

Consider an individual who: <br/>Weighs 80 kg<br/>Is 1.75 meters tall

BMI = 80 ÷ (1.75 × 1.75) ≈ 26.1

This value falls into the Overweight category based on standard guidelines.

Healthy Weight Reference Table (Quick Lookup)

HeightHealthy Weight (BMI 18.5–24.9)Overweight Starts (BMI 25)Obesity Starts (BMI 30)
5' 0"95 - 128 lbs130 - 152 lbs> 152 lbs
5' 1"97 - 132 lbs134 - 159 lbs> 159 lbs
5' 2"101 - 134 lbs137 - 163 lbs> 163 lbs
5' 3"104 - 141 lbs143 - 170 lbs> 170 lbs
5' 4"108 - 146 lbs148 - 174 lbs> 176 lbs
5' 5"110 - 150 lbs152 - 179 lbs> 181 lbs
5' 6"115 - 154 lbs157 - 185 lbs> 187 lbs
5' 7"117 - 159 lbs161 - 190 lbs> 192 lbs
5' 8"121 - 165 lbs168 - 196 lbs> 198 lbs
5' 9"126 - 168 lbs170 - 203 lbs> 203 lbs
5' 10"130 - 174 lbs176 - 209 lbs> 209 lbs
5' 11"132 - 179 lbs181 - 214 lbs> 214 lbs
6' 0"137 - 183 lbs185 - 220 lbs> 220 lbs
6' 1"139 - 187 lbs190 - 225 lbs> 227 lbs
6' 2"143 - 194 lbs196 - 234 lbs> 234 lbs
6' 3"148 - 201 lbs203 - 240 lbs> 240 lbs
6' 4"152 - 205 lbs207 - 245 lbs> 247 lbs

BMI Categories and Meaning

BMI values are grouped into standard categories:

Underweight: BMI below 18.5
Normal weight: BMI 18.5 – 24.9
Overweight: BMI 25.0 – 29.9
Obesity: BMI 30.0 and above

These ranges are used internationally as general health guidelines.

Frequently Asked Questions

What is a healthy BMI range?

For most adults, a BMI between 18.5 and 24.9 is considered healthy.

Is BMI accurate for everyone?

BMI works well as a general screening tool but may be less accurate for athletes, older adults, or people with high muscle mass.

Does BMI differ by gender?

The calculation formula is the same, but health interpretation may vary slightly.

Can BMI predict health risks?

BMI can indicate potential risk but cannot predict individual health outcomes.

Is BMI the same worldwide?

Yes. The standard BMI formula and categories are used globally, though some regions may apply additional guidelines.

Can BMI change quickly?

Yes. Weight changes can affect BMI, especially over short periods.

Should I worry about a single BMI reading?

One measurement alone is not definitive. Long-term trends are more meaningful.

Is BMI used by doctors?

Yes, but usually alongside other clinical assessments.

Does this calculator store my data?

No. All calculations run locally in your browser.

Can BMI replace a medical checkup?

No. It is a starting point, not a substitute for professional medical advice.

Why is waist size important?

Waist circumference measures abdominal fat, which is a key predictor of health risks like type 2 diabetes and heart disease, sometimes even more so than BMI.

Does ethnicity affect BMI interpretation?

Yes. Some ethnic groups (e.g., Asian populations) may have higher health risks at lower BMI values, while others (e.g., Pacific Islanders) may have higher muscle mass.

Is this calculator suitable for children?

No. This calculator is for adults (20+). Children and teens use BMI percentiles based on age and gender.

Can I trust BMI if I am pregnant?

No. BMI calculations are not applicable during pregnancy due to weight gain from the baby and fluid retention.

Does hydration level affect my result?

Yes. Dehydration or excess water retention can cause temporary weight fluctuations that slightly alter your BMI.

What is the best time to weigh myself?

For consistency, weigh yourself in the morning, after using the bathroom and before eating or drinking.

Does bone density affect BMI?

Slightly. While bone structure varies, it typically accounts for a small percentage of total weight compared to muscle and fat.

Limitations of BMI

  • Does not diagnose medical conditions
  • Does not measure body fat directly
  • Does not account for muscle mass
  • Does not reflect overall fitness

BMI should be interpreted cautiously and in context.

Medical Disclaimer

This BMI Calculator provides general information only and is not a substitute for professional medical advice, diagnosis, or treatment.

Always seek the advice of your physician or qualified health provider with any questions regarding a medical condition.

Fact Checked by Expert Toolkit TeamLast Updated: January 2026