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Free Body Metrics Calculator

BMI, Calories &
Body Metrics

Enter your details to instantly calculate your BMI, ideal weight range, daily calorie needs, body fat estimate, and more.

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Fill in your details and click Calculate to see your full body metrics.
Health Disclaimer: These calculations are for informational and educational purposes only. BMI and body metrics are general estimates and do not account for individual health conditions, muscle mass, bone density, or other factors. Always consult a qualified healthcare professional before making changes to your diet or exercise routine.

What is BMI?

Body Mass Index (BMI) is a simple ratio of weight to height squared. It's widely used as a screening tool but has limitations — it doesn't distinguish muscle from fat and can misclassify athletes, elderly individuals, and different ethnic groups.

What is TDEE?

Total Daily Energy Expenditure (TDEE) is the total calories your body burns each day including activity. To lose weight, eat below your TDEE. To gain, eat above it. Most people's TDEE falls between 1,600–2,800 calories depending on size and activity.

BMR vs TDEE

BMR (Basal Metabolic Rate) is the calories your body needs at complete rest — just to keep organs functioning. TDEE multiplies your BMR by an activity factor. BMR is the floor; TDEE is your real daily requirement including movement.

Limitations of BMI

BMI doesn't measure body fat directly. A muscular athlete may have a "overweight" BMI despite low body fat. Conversely, someone with a "normal" BMI can have high body fat (called "skinny fat"). Use BMI as one signal among many, not a definitive health verdict.

Frequently Asked Questions
What is a healthy BMI range? ▾
The WHO defines a healthy BMI as 18.5–24.9. Below 18.5 is underweight, 25–29.9 is overweight, and 30+ is obese. However, these thresholds were developed primarily from European populations. Some health organizations recommend lower thresholds for Asian populations (23 for overweight, 27.5 for obese) as health risks appear at lower BMI values.
Step 1 of 5 ✓ — Great, you have your BMI. Next: find your Body Fat % for a more accurate picture of your composition.
Calculate Body Fat % →
How accurate is the body fat estimate? ▾
The body fat estimate here uses the U.S. Navy circumference method formula — a standard estimation technique. For a precise measurement, use DEXA scanning (most accurate), hydrostatic weighing, or a BodPod. Skin-fold calipers and bioelectrical impedance (bathroom scales) are less accurate but still useful for tracking trends.
What BMR formula does this use? ▾
We use the Mifflin-St Jeor equation, which is widely considered the most accurate for estimating BMR in most people. For men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5. For women: same formula but −161 instead of +5. TDEE is then calculated by multiplying BMR by an activity factor.
How much should I eat to lose weight? ▾
A deficit of 500 calories per day results in roughly 0.5 kg (1 lb) of fat loss per week, as 1 lb of fat ≈ 3,500 calories. This is a sustainable, evidence-based rate. More aggressive deficits can work but risk muscle loss and metabolic adaptation. Most professionals recommend not going below 1,200 calories (women) or 1,500 calories (men) without medical supervision.
What is a healthy body fat percentage? ▾
For men, 10–20% body fat is considered healthy; 2–5% is essential fat. For women, 18–28% is healthy; 10–13% is essential. Athletes typically have lower body fat: male athletes 6–13%, female athletes 14–20%. Above 25% (men) and 32% (women) is generally considered obese by body fat standards.
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How to Use the BMI Calculator

Calculate your Body Mass Index and understand what it means for your health.

01
Choose your measurement system
Select metric (kg/cm) or imperial (lbs/inches). Both give identical results — choose whichever you know off the top of your head.
02
Enter your height
Use your most recent measured height, not what you think you are. Height can change with age — get measured if you're unsure.
03
Enter your weight
Use your current weight, ideally measured in the morning before eating. Weight fluctuates 1–3kg daily due to water, food, and sodium.
04
Read your BMI score
Your BMI is a single number. Under 18.5 is underweight, 18.5–24.9 is healthy, 25–29.9 is overweight, 30+ is obese. These are population-level categories, not individual diagnoses.
05
Review your healthy weight range
The calculator shows the weight range that corresponds to a healthy BMI for your height. This gives you a concrete target if you have weight goals.
06
Understand the limitations
BMI doesn't distinguish between muscle and fat. Athletes often show 'overweight' BMIs. Use it as one data point alongside waist circumference, body fat %, and how you feel.
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💡 Waist circumference is often a better health predictor than BMI. Health risks increase above 35 inches (88cm) for women and 40 inches (102cm) for men.