BMI Calculator

Enter Your Values

Gender

Age (years)

Height (cm)

Weight (kg)

Waist Circumference (cm)

Activity Level

What the BMI Calculator Does

This advanced BMI calculator goes beyond the basic BMI formula. It calculates your Body Mass Index, estimates body fat using the Relative Fat Mass (RFM) method, computes your Total Daily Energy Expenditure (TDEE), ideal body weight, and daily water needs — all from a single set of inputs.

How to Use This Calculator

Step-by-Step Guide

Enter Your Profile

Select your gender and enter your age, height, and weight accurately.

Add Waist Measurement

Measure your waist at the navel level for accurate body fat and risk assessment.

Select Activity Level

Choose the level that best reflects your typical week, not your best week.

Review Your Results

Check all six result cards, the visual BMI scale, macro breakdown, and risk assessment.

Understanding BMI Ranges

⚔️ Underweight (<18.5)

May indicate nutritional deficiency, eating disorders, or other health conditions. Associated with weakened immunity and bone loss.

✅ Normal (18.5-24.9)

Generally associated with the lowest health risks. Maintain through balanced diet and regular physical activity.

⚠️ Overweight (25-29.9)

Increased risk of cardiovascular disease, type 2 diabetes, and high blood pressure. Lifestyle changes recommended.

🚨 Obese (30+)

Significantly elevated health risks including heart disease, stroke, and certain cancers. Medical consultation advised.

BMI Limitations

BMI is a population-level screening tool, not a diagnostic measure. It does not directly measure body fat, distinguish between fat and muscle mass, or account for fat distribution. Athletes, elderly individuals, and pregnant women may get misleading results. Always pair BMI with other assessments like waist circumference, body fat percentage, and blood work for a complete health picture.

Frequently Asked Questions

BMI stands for Body Mass Index. It is a numerical value calculated from your weight and height that provides a general indication of whether you have a healthy body weight.

BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat mass, so athletes may have a high BMI despite being healthy. It's best used alongside other measurements like waist circumference and body fat percentage.

A healthy BMI is generally considered to be between 18.5 and 24.9 kg/m². However, the ideal range can vary by age, sex, ethnicity, and individual factors. The WHO and NIH both use these standard categories.

BMI is calculated by dividing your weight in kilograms by your height in meters squared: BMI = weight (kg) / height (m)². For imperial units, multiply the result by 703.

The BMI formula is the same for both sexes, but body fat distribution differs. Women naturally have higher body fat percentages than men at the same BMI. That's why this calculator also estimates body fat using the Relative Fat Mass (RFM) formula.

Yes. BMI doesn't account for muscle mass. A bodybuilder or athlete with significant muscle may have a BMI in the 'overweight' or 'obese' range while being perfectly healthy. In such cases, body fat percentage is a better indicator.

Disclaimer: This calculator is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider before making health decisions.