BMR Calculator

BMR Calculator – Calculate Your Basal Metabolic Rate & Daily Calorie Needs

This BMR Calculator helps you accurately estimate your Basal Metabolic Rate (BMR), which is the number of calories your body burns every day at complete rest. BMR represents the minimum energy required to keep you alive—fueling vital functions such as breathing, blood circulation, brain activity, hormone regulation, and cell repair.

Health professionals, nutritionists, and fitness experts worldwide rely on BMR calculations—often aligned with guidance from the World Health Organization (WHO) as the foundation for calorie planning, weight management, and metabolic health assessment.

What Is Basal Metabolic Rate (BMR)?

Basal Metabolic Rate (BMR) is the amount of energy, measured in calories, that your body requires in a 24-hour period to maintain essential life-sustaining functions while at rest. These functions include heart activity, lung function, kidney operation, nervous system activity, and maintaining core body temperature.

Even if you were to lie in bed all day without moving, your body would still burn calories to stay alive. That energy expenditure is your BMR. For most people, BMR accounts for 60–75% of total daily calorie burn.

How BMR Is Calculated (Mifflin-St Jeor Formula)

This calculator uses the Mifflin-St Jeor equation, which is widely regarded as the most accurate BMR formula for adults based on modern metabolic research.

Example:A 30-year-old male weighing 70 kg and 175 cm tall would have:

This means his body burns approximately 1,648.75 calories per day at rest.

BMR vs TDEE – What's the Difference?

BMR is often confused with TDEE (Total Daily Energy Expenditure), but they are not the same.

• BMR: Calories burned at complete rest
• TDEE: BMR + calories burned from daily activity, exercise, and movement

To estimate your actual daily calorie needs, your BMR is multiplied by an activity factor. This makes BMR the foundation of every accurate calorie, diet, or fitness plan.

Who Should Use This BMR Calculator?

This BMR Calculator is ideal for adults who want to understand how their body uses energy and how many calories they need each day.

• People planning weight loss or fat reduction
• Individuals trying to gain muscle or healthy weight
• Fitness beginners creating workout plans
• Dieters tracking calorie intake
• Office workers with sedentary lifestyles
• Anyone learning about metabolism and nutrition

Why Knowing Your BMR Is Important

Without knowing your BMR, calorie planning becomes guesswork. Eating far below your BMR can slow metabolism and cause fatigue, while consistently eating far above your needs can lead to unwanted fat gain.

Knowing your BMR helps you:

• Avoid extreme dieting and metabolic slowdown
• Create sustainable weight-loss plans
• Fuel workouts and muscle recovery properly
• Understand why weight changes occur

Limitations of BMR Calculations

While BMR is extremely useful, it is still an estimate and not a perfect measurement of metabolism.

BMR calculations may be less accurate for:

• Athletes with very high muscle mass
• Pregnant or breastfeeding women
• People with thyroid or hormonal disorders
• Elderly individuals with muscle loss

Genetics, sleep quality, stress, illness, and body composition also influence metabolism but are not fully captured by any formula.

What to Do After Calculating Your BMR

Once you know your BMR, the next step is adjusting calorie intake based on activity level and health goals. For weight loss, calorie intake is usually kept slightly below TDEE—not below BMR. For muscle gain, intake is increased gradually above daily needs.

This BMR Calculator is an educational and planning tool. For medical conditions or significant weight changes, consult a qualified healthcare professional or registered dietitian.