BMI Calculator
Calculate your Body Mass Index instantly using metric or imperial units. Get your weight category, healthy range, and health insights.
How to Use the BMI Calculator
Choose Unit System: Select either Metric (cm/kg) or Imperial (ft/lbs) units from the toggle options at the top of the tool.
Enter Your Height: Type your height in centimeters if using metric, or enter feet and inches separately if using imperial.
Enter Your Weight: Type your weight in kilograms (metric) or pounds (imperial) in the weight field.
Click Calculate BMI: Press the Calculate BMI button to instantly see your BMI value, weight category, and the visual indicator bar.
Review Your Results: Read your BMI score, weight category, healthy weight range for your height, and how much weight you may need to lose or gain to reach the healthy range.
Key Features
Instant Calculation
Get your BMI result in real time with a single click. No delays, no loading screens.
Metric & Imperial
Switch between cm/kg and ft/lbs seamlessly. Works for users worldwide.
Visual BMI Bar
An intuitive color-coded bar shows exactly where your BMI sits on the standard scale.
Healthy Range Info
See your ideal weight range for your height and how much to adjust to reach it.
100% Private
All calculations run in your browser. No data is stored, sent, or shared anywhere.
Asian BMI Note
Includes an important note about WHO's lower BMI cutoffs recommended for South Asian and Asian adults.
How BMI Is Calculated
Body Mass Index (BMI) is calculated using a simple ratio of weight to the square of height. The World Health Organization established this formula as a standard population-level screening tool for weight-related health risks.
- Weight — Your body weight in kilograms or pounds
- Height — Your height converted to meters (metric) or total inches (imperial)
- 703 — Conversion factor that adjusts pounds and inches to match metric results
For example, a person who is 170 cm tall and weighs 68 kg has a BMI of: 68 ÷ (1.70 × 1.70) = 68 ÷ 2.89 ≈ 23.5 — which falls in the Normal weight category.
The four standard BMI categories are: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25–29.9), and Obese (30 and above). For South Asian adults, overweight is flagged at BMI 23.
Practical Examples
BMI = 62 ÷ (1.58²) = 62 ÷ 2.4964 = 24.8
BMI = 95 ÷ (1.75²) = 95 ÷ 3.0625 = 31.0
BMI = (185 × 703) ÷ (70²) = 130,055 ÷ 4,900 = 26.5
BMI = 47 ÷ (1.62²) = 47 ÷ 2.6244 = 17.9
What Is BMI (Body Mass Index)?
BMI stands for Body Mass Index — a numerical value derived from a person's height and weight. Developed in the 19th century by mathematician Adolphe Quetelet, BMI was later adopted by the World Health Organization as a standardized screening tool to classify adults into weight categories associated with health risk levels.
It's important to understand that BMI is a population-level screening measure, not a direct diagnostic tool. Two people can have the same BMI but very different body compositions. A bodybuilder with high muscle mass may register as overweight, while someone with low muscle mass and high body fat might register as normal. Always use BMI alongside other health indicators like waist circumference, blood pressure, and cholesterol levels.
For Indian and South Asian adults specifically, the risk of metabolic diseases like type 2 diabetes and cardiovascular conditions begins at a lower BMI than Western populations. Indian health guidelines suggest screening for overweight at BMI 23 and obesity at BMI 27.5, making context-aware interpretation especially important.
BMI in Your Language
Want to understand BMI in depth — how it's used, its limitations, and what to do with your results?
Read the Full Guide on BMI →Frequently Asked Questions
Is this BMI calculator free to use?
Yes, this BMI calculator is completely free to use with no registration, login, or hidden charges required. Use it as many times as you need.
What is a healthy BMI range?
A BMI between 18.5 and 24.9 is considered healthy for most adults. Values below 18.5 indicate underweight, 25–29.9 indicate overweight, and 30 or above indicate obesity.
Does BMI differ for Asian populations including Indians?
Yes. The WHO and Indian health authorities recommend lower BMI cutoffs for South Asians. Overweight begins at BMI 23 and obesity at BMI 27.5 for Asian adults due to differences in body fat distribution and metabolic risk.
Can I use this BMI calculator for children?
This calculator is designed for adults aged 18 and above. Children and teenagers require age- and sex-specific BMI percentile charts. Please consult a pediatrician for children's BMI assessment.
Does this tool support both metric and imperial units?
Yes, this BMI calculator supports both metric units (centimeters and kilograms) and imperial units (feet, inches, and pounds). Toggle between them before entering your data.
How accurate is BMI as a health measure?
BMI is a useful screening tool but does not directly measure body fat or overall health. Athletes may have high BMI due to muscle mass. Use BMI alongside waist circumference, blood tests, and professional medical advice.
What is the BMI formula used in this calculator?
For metric: BMI = weight (kg) ÷ height² (m²). For imperial: BMI = (weight in lbs × 703) ÷ height² (inches²). These are standard WHO-established formulas.
Does BMI account for age and gender?
Standard adult BMI does not adjust for age or gender. However, older adults may carry more fat at the same BMI, and women naturally have higher body fat than men at equivalent BMI values.
What should I do if my BMI is outside the healthy range?
If your BMI is outside the 18.5–24.9 range, consult a registered doctor or dietitian for personalized guidance. BMI alone is not a diagnosis — it is a screening indicator.
Is my data stored when I use this calculator?
No. All calculations happen entirely in your browser. No personal data is sent to any server or stored anywhere. Your privacy is fully protected.
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