⚖️

BMI Calculator

numberClient-side utility

Body mass index (BMI) is a commonly used screening measure that compares an adult's body weight with height. Calculating it manually requires converting units, squaring the height measurement, and applying the correct formula. This browser-based adult BMI calculator updates the result as you enter your measurements. Choose metric units (kilograms and centimeters) or imperial units (pounds and inches), then review your BMI and corresponding adult screening category. BMI is not a diagnosis and should be interpreted together with other health information.

✓ In-Browser Execution✓ Free & No Usage Cap✓ Zero Server Data Storage

⚖️ BMI Calculator — Body Mass Index

Calculate your Body Mass Index and see your health category. Supports metric and imperial units. Free, private, browser-only.

Unit

Weight (kg)

Height (cm)

≤18.5

18.5–25

25–30

≥30

📖How to Use This Tool

What is a BMI Calculator?

Body Mass Index (BMI) is a screening measure calculated from body weight and height. In metric units, BMI equals weight in kilograms divided by height in meters squared (kg/m²). It provides a simple standardized value, but it does not directly measure body fat, muscle mass, fitness, or overall health.

For adults, commonly used screening categories are below 18.5 for underweight, 18.5 to less than 25 for the healthy-weight range, 25 to less than 30 for overweight, and 30 or higher for the obesity range. These fixed categories are intended for adults aged 20 and older and should not be used for children or teenagers, who require age- and sex-specific growth references.

How to use it

Choose metric (kg/cm) or imperial (lb/in) units.
Enter your weight and height. The result updates live as you type.
Review your BMI (shown to one decimal place), the screening category, and the healthy weight range for your height.

This calculator is intended for adults only. It is not suitable for children or teenagers.

Why use this over alternatives

This calculator provides metric and imperial BMI calculations without requiring an account or app installation. The calculation runs locally in your browser, and the measurements entered into the calculator are not intentionally sent to our servers.

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❓Frequently Asked Questions

Q.How is Body Mass Index calculated?

In metric units, BMI equals weight in kilograms divided by height in meters squared (kg/m²). For imperial units, multiply weight in pounds by 703, then divide by height in inches squared. The calculator applies the correct formula automatically and displays the result rounded to one decimal place.

Q.Can BMI tell body fat apart from muscle?

No. BMI is calculated from height and total body weight, so it does not directly distinguish body fat from muscle, bone, or other tissues. People with high muscle mass may have a BMI in the overweight range despite having relatively low body fat. BMI should therefore be interpreted alongside other health and body-composition information.

Q.What adult BMI categories does this calculator use?

This calculator uses standard adult screening thresholds: below 18.5 is underweight, 18.5 to less than 25 is the healthy-weight range, 25 to less than 30 is overweight, and 30 or higher is in the obesity range. These fixed thresholds are intended for adults and should not be used to classify children or teenagers.

Q.Is BMI a medical diagnosis?

No. BMI is a screening measure, not a diagnosis of body fat, obesity-related disease, or overall health. A healthcare professional may consider BMI together with medical history, waist measurements, laboratory results, body composition, medications, and other individual factors.

Q.Can this calculator be used for children or teenagers?

No. This calculator uses fixed adult BMI categories. BMI for children and teenagers must be interpreted using age- and sex-specific growth references. Use a dedicated child and teen BMI calculator or consult a qualified healthcare professional.

Q.When may BMI require additional interpretation?

BMI may not accurately reflect body composition or health risk for every individual. Pregnancy, high muscularity, changes in muscle mass, and other personal or medical factors can affect how a BMI result should be interpreted. Consult a healthcare professional if you have concerns about weight, nutrition, growth, or health risk.

Q.Is my height or weight sent to a server?

BMI calculations are performed locally in your browser using client-side JavaScript. The tool does not intentionally send the height and weight entered in the calculator to our servers. Avoid entering personal information on shared or untrusted devices. ---

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