What Is a BMR Calculator?

A BMR calculator is a free online tool that estimates your Basal Metabolic Rate — the number of calories your body burns every day at complete rest, just to sustain vital functions like breathing, circulation, cell repair, and temperature regulation. Enter your age, sex, height, and weight to instantly receive your daily calorie baseline — the essential starting point for any weight loss, muscle gain, or calorie maintenance plan.

BMR Formula: Mifflin-St Jeor vs Harris-Benedict

Two clinically validated equations power every basal metabolic rate calculator. The Mifflin-St Jeor equation (recommended by the Academy of Nutrition and Dietetics as the most accurate for healthy adults) is:

Men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 Women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161

Quick example: A 30-year-old woman, 165 cm tall, weighing 65 kg: BMR = (10 × 65) + (6.25 × 165) − (5 × 30) − 161 = 650 + 1,031.25 − 150 − 161 = 1,370 calories/day at rest

BMR → TDEE: Your Actual Daily Calorie Needs

BMR alone is not your daily calorie target. Multiply BMR by your activity factor to get TDEE (Total Daily Energy Expenditure) — what you actually burn each day:

Calorie targets from TDEE:

• 🟢 Maintain weight: Eat at TDEE
• 🔵 Lose weight: Eat 500 cal below TDEE (~0.5 kg/week loss)
• 🔴 Gain muscle: Eat 300–500 cal above TDEE

⚠️ Never eat below your BMR. Doing so causes metabolic slowdown, muscle loss, and hormonal disruption.

Why Use Click2Calculate’s Online BMR Calculator?

• ✅ Mifflin-St Jeor & Harris-Benedict — both validated equations available
• ✅ TDEE calculator built-in — all five activity levels auto-calculated
• ✅ BMR for men and women — sex-specific formula applied automatically
• ✅ Metric & imperial — switch between kg/cm and lbs/ft instantly
• ✅ Goal-based calorie targets — weight loss, maintenance & muscle gain outputs
• ✅ BMR vs RMR explained — understand the difference between resting metabolic rates

Use this free BMR calculator online to stop guessing your calorie needs — and start your weight loss or fitness goal with a number that is personal, accurate, and science-backed.

Disclaimer: BMR estimates are based on population-level equations and are not a substitute for clinical metabolic testing. Individual results vary based on body composition, health conditions, and hormonal factors. Consult a registered dietitian or healthcare professional before making significant dietary changes.