Science-based health calculators for weight management, body composition, and nutrition planning. Track your fitness journey with accurate, easy-to-use tools.
Calculate Body Mass Index and see your weight category using WHO standards. Get healthy weight range for your height.
Calculate TDEE and daily calorie needs for weight loss, maintenance, or muscle gain goals with Mifflin-St Jeor formula.
Estimate body fat percentage using U.S. Navy method with simple circumference measurements.
Whether you're starting a weight loss journey, trying to gain muscle, or simply want to understand your current health metrics, these calculators provide data-driven insights using formulas from WHO, CDC, and sports science research.
Choose the right tool for your goal:
All calculators use evidence-based formulas (Mifflin-St Jeor equation for metabolism, U.S. Navy method for body fat, WHO standards for BMI). Results are estimates for planning purposes—always consult a doctor or registered dietitian for personalized medical advice.
BMI is a useful screening tool but has limitations. It doesn't account for muscle mass, so athletes may classify as "overweight" despite being healthy. It also doesn't measure body fat distribution. Use BMI as one indicator alongside body fat percentage, waist circumference, and overall health markers. For personalized assessment, consult a doctor.
A safe deficit is 500-750 calories below your TDEE (Total Daily Energy Expenditure), resulting in 1-1.5 lbs loss per week. Never eat below 1200 calories (women) or 1500 calories (men) without medical supervision. Use our Calorie Calculator to find your TDEE, then subtract 500-750 for a sustainable deficit that preserves muscle mass.
BMI uses only height and weight, while body fat percentage estimates how much of your weight is fat vs. lean mass (muscle, bone, organs). Two people with the same BMI can have very different body compositions. Body fat percentage is more informative for athletes or people with high muscle mass. Use both metrics together for a complete picture.
Check BMI and body fat monthly, not daily. Daily weight fluctuates due to water retention, food timing, and hormones. Track measurements at the same time (e.g., morning before eating) for consistency. Focus on trends over 4-6 weeks rather than day-to-day changes.
Yes! The Calorie Calculator can set a caloric surplus for muscle gain (usually 10-20% above TDEE). Body Fat Calculator helps track if you're gaining muscle or just fat. Aim to gain 0.5-1 lb per week while strength training. If body fat percentage increases too fast, reduce your surplus.