BMI & BMR Calorie Calculator
Calculate BMI with WHO categories, BMR (Mifflin-St Jeor), daily calorie needs (TDEE), and weight-goal targets.
BMI & Calorie Calc — interactive calculator, computed instantly in your browser.
BMI, BMR & TDEE Guide: WHO Categories and Mifflin-St Jeor Calories
Body Mass Index Categories at a Glance
Key Takeaway: BMI 18.5–24.9 is the WHO healthy range, but athletes with high muscle mass should pair BMI with waist measurements and body-fat estimates.
Body Mass Index (BMI) screens weight status using height and weight, while Basal Metabolic Rate (BMR) estimates the calories your body burns at rest. Together with activity multipliers (TDEE), they define your daily calorie budget for losing, maintaining, or gaining weight.
1. BMI Formula & WHO Categories
Example: 70 kg at 1.75 m → 70 / 3.0625 = 22.9 (Healthy). Categories: below 18.5 Underweight, 18.5–24.9 Healthy, 25–29.9 Overweight, 30+ Obese.
2. BMR — Mifflin-St Jeor Equation
A 30-year-old man (70 kg, 175 cm): 700 + 1093.75 − 150 + 5 = 1,649 kcal/day at rest. Multiply by activity (Sedentary 1.2 → Very Active 1.9) to get TDEE.
3. Setting Calorie Targets
- Fat loss: TDEE − 500 kcal/day (≈0.5 kg/week). Never drop below 1,500 (men) or 1,200 (women) without medical supervision.
- Maintenance: Eat at TDEE and track weight trends over 2–3 weeks.
- Muscle gain: TDEE + 250–350 kcal/day with progressive resistance training and 1.6–2.2 g protein per kg bodyweight.
🔗 Health & Body Metric Cross-References
Knowing your BMI and daily calorie expenditure is the foundation of any diet or training plan. Explore our 💪 Health Hub for body-metric tools.
Convert body weight units or calculate your exact chronological age with the companion tools below.
Frequently Asked Questions (BMI & Calorie Calc)
BMI cannot distinguish muscle from fat. Strength athletes and muscular builds often score 25+ while carrying low body fat. Cross-check with waist circumference (below 94 cm men / 80 cm women) or body-fat percentage.
Mifflin-St Jeor (1990) is validated as more accurate for modern body compositions and is the default in most clinical settings. Harris-Benedict (1919, revised 1984) typically overestimates by 5-10%.
Hold any target for 2-3 weeks, then adjust by 150-200 kcal. Daily weight fluctuates with water and glycogen, so judge trends using weekly averages, not single weigh-ins.