Calculate your BMI with category breakdown. Premium unlocks BMR, TDEE and daily macro calculations with personalised calorie recommendations. Free health calculator.
What Is BMI Calculator & TDEE Calculator Online?
Body Mass Index (BMI) is a simple screening tool that estimates body fat based on your height and weight. It divides your weight in kilograms by your height in metres squared (kg/m²). The resulting number places you in a category: underweight (below 18.5), healthy weight (18.5–24.9), overweight (25–29.9) or obese (30 and above).
While BMI is widely used by health professionals as a quick assessment tool, it has limitations. It does not distinguish between muscle and fat, so athletic individuals may be classified as overweight despite having low body fat. It also does not account for factors like age, gender, ethnicity or fat distribution. Use BMI as one data point alongside other health indicators, not as a definitive measure.
How to Use This Tool
Enter your height using your preferred unit (cm, feet/inches, or metres).
Enter your weight in kilograms or pounds.
View your BMI score and the category it falls into.
Read the healthy weight range calculated for your height.
Premium users can track BMI over time and see trends.
Tips & Best Practices
BMI is a screening tool, not a diagnostic — consult a healthcare professional for personalised health advice.
For a more complete picture, combine BMI with waist circumference and body fat percentage measurements.
Athletes and people with high muscle mass may have elevated BMI without being overweight.
BMI thresholds differ for children and teenagers — this calculator is designed for adults.
Common Use Cases
Getting a quick health screening estimate based on height and weight.
Calculating the weight range considered healthy for your height.
Tracking BMI changes over time during a fitness or weight management programme.
Understanding BMI categories for health insurance, medical or fitness assessments.
Frequently Asked Questions
What is BMI?
Body Mass Index (BMI) is calculated by dividing your weight in kilograms by your height in metres squared. A BMI of 18.5-24.9 is considered healthy for most adults.
What is TDEE?
Total Daily Energy Expenditure is the estimated number of calories you burn per day including exercise. It is calculated by multiplying your BMR by an activity factor.