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BMI Calculator (Body Mass Index) – Accurate, Fast, Mobile-Friendly

BMI Calculator (Body Mass Index)

Free, accurate, and global — metric and imperial units, instant results, healthy weight range, and a helpful chart.

Calculate your BMI

No sliders. Enter your values and get instant results.

Kilograms (kg)
Centimeters (cm)
Enter your weight and height, then select Calculate BMI.
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BMI
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Category
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Healthy weight range
Underweight: below 18.5 Healthy: 18.5–24.9 Overweight: 25–29.9 Obesity: 30+

BMI categories (visual guide)

This chart helps visualize categories. Your current category highlights after calculation.

What is BMI (Body Mass Index)?

Body Mass Index (BMI) is a simple screening measure that compares your weight to your height to estimate whether your weight falls within a healthy range. It is calculated by dividing your weight by the square of your height. Healthcare professionals, students, and athletes often use BMI as a quick, global standard for assessing weight-related health risk.

Formula and units (global support)

Metric: BMI = weight (kg) / [height (m)]². If your height is in centimeters, divide by 100 to convert to meters before squaring.

Imperial: BMI = 703 × weight (lb) / [height (in)]². Our calculator accepts feet and inches, then converts to total inches for accuracy.

Categories and interpretation

Most adult BMI results are grouped as: Underweight (below 18.5), Healthy (18.5–24.9), Overweight (25–29.9), and Obesity (30+). While BMI is useful, it does not directly measure body fat or distribution. For individuals with high muscle mass, seniors, or different body compositions, complementary measures (waist circumference, body fat percentage, and clinical assessment) provide more context.

Why students and professionals use BMI

Quick screening:

Ideal for class projects, patient triage, wellness programs, and fitness tracking where a fast, comparable metric is needed.

Global consistency:

Uniform categories make BMI comparable across countries, education levels, and workplaces using either metric or imperial units.

Next steps:

Combine BMI with lifestyle habits, physical activity, and professional guidance to build a sustainable health plan.

Tip: If your BMI is outside the healthy range, look at sustainable changes: balanced nutrition, regular activity, and sleep. Small, consistent steps compound over time.

Healthy weight range for your height

Your healthy range is estimated by reversing the BMI formula using 18.5 and 24.9 as the bounds. We calculate and display this range in your selected unit system to make it actionable.

How-To: Add this BMI calculator to your website

  1. Copy: Copy this entire single-file HTML.
  2. Paste: Add it to your page or CMS (HTML block or template).
  3. Publish: Save, publish, and open the page.
  4. Test: Check on mobiles, iPads, tablets, laptops, and desktops.
  5. Customize: Edit colors, meta tags, and content as needed.

FAQs

HOW TO calculate BMI accurately?

Choose your unit system, enter weight and height, then select “Calculate BMI.” Use precise values (e.g., decimal centimeters or inches) for best accuracy.

HOW TO read my BMI category?

Once calculated, your category appears next to your BMI (Underweight, Healthy, Overweight, Obesity), and the chart highlights it visually.

HOW TO switch between metric and imperial?

Use the unit chips at the top of the calculator. The inputs automatically switch between kg/cm and lb/ft+in.

HOW TO find my healthy weight range?

After calculating, see the “Healthy weight range” card. It’s computed from BMI 18.5–24.9 for your height and shown in your current units.

HOW TO improve my BMI safely?

Focus on gradual changes: nutrition quality, consistent physical activity, sleep, and hydration. For personalized guidance, consult a qualified health professional.

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