What is the formula for calculating BMI?

Metric: `BMI = weight (kg) / [height (m)]²`. Imperial: `BMI = [weight (lbs) / (height (in))²] × 703`.

What is considered a normal healthy BMI?

According to the World Health Organization (WHO), a normal, healthy BMI for adults ranges between 18.5 and 24.9.

Why can BMI be inaccurate for athletes and bodybuilders?

BMI does not differentiate between muscle mass and fat mass. Muscular athletes often have high BMI scores indicating 'overweight' despite having very low body fat percentages.

What is the healthy weight range for my height?

Multiply the square of your height in meters by 18.5 for minimum healthy weight and by 24.9 for maximum healthy weight (`Min Weight = 18.5 × h²`, `Max Weight = 24.9 × h²`).

How does BMI differ for children and teenagers?

For children and teens (ages 2–20), BMI is interpreted using age-and-sex-specific growth percentiles (e.g., 5th to 85th percentile is healthy weight) rather than static adult categories.

Does BMI distinguish between muscle mass and body fat percentage?

No. Standard BMI relies purely on height and weight. Highly muscular athletes may register as 'overweight' despite having low body fat, which is why body fat calipers or DEXA scans provide supplementary clarity.

Health & Fitness Cluster

BMI Calculator (Body Mass Index & Weight Categories)

Calculate Body Mass Index (BMI) and healthy weight ranges using metric or imperial units.

TL;DR: BMI Calculator computes your Body Mass Index score using the standard formula $\text{BMI} = \text{weight (kg)} / [\text{height (m)}]^2$ and classifies results according to World Health Organization (WHO) standards.

Units

Weight (kg)

Height (cm)

What Is Body Mass Index (BMI) and What Are the WHO Categories?

Body Mass Index (BMI) is a screening metric that assesses body weight relative to height: BMI = weight (kg) / [height (m)]² or BMI = [weight (lbs) / height (in)²] × 703. WHO categories are: Underweight (< 18.5), Normal Weight (18.5–24.9), Overweight (25.0–29.9), and Obese (≥ 30.0).

How to Use the BMI Calculator

Our BMI Calculator performs high-precision mathematical operations directly in your browser with zero latency and complete client-side privacy.

Select unit system: Metric (Centimeters and Kilograms) OR Imperial (Feet/Inches and Pounds).
Enter your Age and Gender (for adult context and child BMI percentiles).
Input your exact Height and current Body Weight.
Click 'Calculate BMI' to view your numerical score and WHO weight classification.
Review your calculated healthy weight range (BMI 18.5–24.9).

Mathematical Formula & Equations

Classifies body weight into WHO categories: Underweight (<18.5), Healthy (18.5–24.9), Overweight (25–29.9), and Obese (30+).

\[ \text{BMI} = \frac{\text{Weight (kg)}}{[\text{Height (m)}]^2} = \frac{\text{Weight (lb)} \times 703}{[\text{Height (in)}]^2} \]

Calculation Example

A person weighing 72 kg at 1.78 m height: $$\text{BMI} = \frac{72}{1.78^2} = \frac{72}{3.1684} = 22.72 \text{ (Healthy Weight)}$$

100% Client-Side Privacy & Data Security

All calculations, amortization schedules, variables, and sensitive numerical datasets execute 100% locally in your web browser memory. Your financial, medical, and personal values are never transmitted, logged, or uploaded to any external server.

Frequently Asked Questions

: Metric: `BMI = weight (kg) / [height (m)]²`. Imperial: `BMI = [weight (lbs) / (height (in))²] × 703`.
: According to the World Health Organization (WHO), a normal, healthy BMI for adults ranges between 18.5 and 24.9.
: BMI does not differentiate between muscle mass and fat mass. Muscular athletes often have high BMI scores indicating 'overweight' despite having very low body fat percentages.
: Multiply the square of your height in meters by 18.5 for minimum healthy weight and by 24.9 for maximum healthy weight (`Min Weight = 18.5 × h²`, `Max Weight = 24.9 × h²`).
: For children and teens (ages 2–20), BMI is interpreted using age-and-sex-specific growth percentiles (e.g., 5th to 85th percentile is healthy weight) rather than static adult categories.
: No. Standard BMI relies purely on height and weight. Highly muscular athletes may register as 'overweight' despite having low body fat, which is why body fat calipers or DEXA scans provide supplementary clarity.

Cite This Calculator

Need to reference this online calculator in a financial proposal, academic paper, blog post, or classroom curriculum? Copy a citation below.

NexLove.org. (2026). BMI Calculator [Online Calculation Tool]. https://nexlove.org/tools/bmi-calculator

“BMI Calculator.” NexLove.org, 2026, nexlove.org/tools/bmi-calculator.

NexLove.org (2026) BMI Calculator. Available at: https://nexlove.org/tools/bmi-calculator (Accessed: 2026).

@misc{nexlove_bmi_calculator,
  title = {BMI Calculator},
  author = {{NexLove.org}},
  year = {2026},
  url = {https://nexlove.org/tools/bmi-calculator}
}

Embed This Tool

Add the live BMI Calculator to your own website with this snippet — it loads the real, working calculator in an iframe.

<iframe src="https://nexlove.org/embed/bmi-calculator.html" width="100%" height="600" style="border:1px solid #e2e8f0;border-radius:12px" title="BMI Calculator — NexLove.org" loading="lazy"></iframe>

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