Free BMI Calculator

Calculate your Body Mass Index, healthy weight range, and body fat estimate. Free fitness tool by TrainexAI.

Your Measurements

Your Results

—

BMI = weight (kg) / height² (m)

Where you fall on the BMI scale

Underweight
<18.5 Normal
18.5–24.9 Overweight
25–29.9 Obese
>30

BMI Value —

Healthy Weight Range —

Estimated Body Fat % —

Weight to Lose/Gain —

What should I do?

—

Get a personalized plan based on your BMI and goals

Get a Personalized Plan

Track your calories with AI-powered meal plans

Calorie Calculator

BMI Categories & What They Mean

Category	BMI Range	Health Risk
Underweight	Below 18.5	Nutritional deficiency, weakened immunity, bone loss
Normal Weight	18.5 – 24.9	Lowest health risk — maintain with balanced diet & exercise
Overweight	25 – 29.9	Increased risk of heart disease, type 2 diabetes, hypertension
Obese Class I	30 – 34.9	High risk — significant lifestyle changes recommended
Obese Class II+	35 and above	Very high risk — medical consultation strongly advised

Note: BMI is a screening tool, not a diagnostic measure. It does not account for muscle mass, bone density, or fat distribution. Athletes may have a high BMI despite low body fat. Consult a healthcare professional for a complete assessment.

What is BMI?

BMI (Body Mass Index) is a simple numerical value calculated from your height and weight. The formula is: BMI = weight (kg) ÷ height² (m²). It was developed by Belgian mathematician Adolphe Quetelet in the 1830s and is now used worldwide as a quick screening tool for weight categories.

A BMI between 18.5 and 24.9 is considered normal for most adults. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is classified as obese. These thresholds are set by the World Health Organization (WHO) and are used by doctors globally.

While BMI is a useful starting point, it has limitations. It doesn't distinguish between fat and muscle — a bodybuilder may have a high BMI despite very low body fat. It also doesn't account for where fat is stored in the body, which matters for health risk. Use it alongside other measures like waist circumference and body fat percentage for a fuller picture.

BMI Chart for Indians

Research suggests that South Asians, including Indians, tend to have higher body fat percentages at the same BMI compared to Western populations. The Indian Council of Medical Research (ICMR) and several studies recommend lower BMI cutoffs for Indians:

Category	Standard WHO	Recommended for Indians
Underweight	Below 18.5	Below 18.5
Normal	18.5 – 24.9	18.5 – 22.9
Overweight	25 – 29.9	23 – 24.9
Obese	30+	25+

This means an Indian with a BMI of 24 may already be at elevated risk for diabetes and cardiovascular disease, even though the standard WHO chart classifies them as "normal." If you're of South Asian descent, aim for a BMI closer to 22–23 for optimal health.

Healthy BMI Range

For most adults aged 18–65, a BMI between 18.5 and 24.9 is considered healthy. For older adults (65+), a slightly higher BMI of 22–27 may be protective against bone loss and frailty. For children and teenagers, BMI is interpreted differently using age- and sex-specific percentile charts.

The healthiest approach is to combine a normal BMI with regular physical activity, a balanced diet, adequate sleep, and low stress. TrainexAI's AI-powered platform helps you build sustainable habits across all these dimensions — from personalized meal plans to real-time workout coaching.

Ready to move toward your healthy BMI? Start your free trial and get a plan built around your exact numbers.