How BMR is Calculated

BMR is calculated using the Mifflin-St Jeor Equation

BMR Formula

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

This value represents how many calories your body needs per day at rest.

Understanding Your BMR (Basal Metabolic Rate)

When it comes to health, fitness, and weight management, one of the most important numbers to know is your BMR, or Basal Metabolic Rate. But what exactly does it mean, and why should you care? Let's break it down in simple terms.

What is BMR?

Your Basal Metabolic Rate is the number of calories your body needs to perform basic functions while you are at complete rest. These are the essential activities that keep you alive, such as:

  • Breathing
  • Pumping blood
  • Maintaining body temperature
  • Cell repair and growth
  • Proper functioning of organs

In short, BMR is the minimum energy requirement your body needs to survive each day, even if you did nothing but lie in bed all day.

Why is BMR Important?

Knowing your BMR is important because it acts as the foundation for all other calorie calculations. It helps you understand:

  • How many calories you burn at rest – This is your baseline energy expenditure.
  • How much to eat for weight loss, gain, or maintenance – If you eat fewer calories than your body burns, you'll lose weight; if you eat more, you'll gain.
  • How to plan diets and workouts effectively – Your BMR gives you a personalized starting point instead of relying on generic numbers.

How is BMR Calculated?

There are different formulas to estimate BMR, but one of the most commonly used is the Mifflin-St Jeor Equation.

For men:
BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age(years) + 5

For women:
BMR = 10 × weight(kg) + 6.25 × height(cm) – 5 × age(years) – 161

This equation takes into account your age, gender, weight, and height, making it more accurate than older formulas.

BMR vs TDEE – What's the Difference?

A lot of people confuse BMR with TDEE (Total Daily Energy Expenditure). Here's the key difference:

  • BMR = Calories burned at complete rest.
  • TDEE = BMR + calories burned from daily activities and exercise.

For example:
If your BMR is 1,500 calories but you move around, go to work, and exercise, your TDEE might be around 2,200 calories.
That means you would need to eat about 2,200 calories per day to maintain your weight.

Factors That Affect BMR

Not everyone has the same BMR. Several factors can influence how many calories your body burns at rest:

  • Age – BMR decreases as you get older because muscle mass tends to decline.
  • Gender – Men usually have higher BMRs than women due to more muscle mass.
  • Weight & Height – Larger bodies require more energy to function.
  • Muscle Mass – Muscles burn more calories than fat, even at rest.
  • Genetics – Some people naturally have faster or slower metabolisms.
  • Hormones – Thyroid and other hormones can impact how quickly your body burns energy.

How to Use Your BMR for Weight Goals

Once you know your BMR, you can make smarter choices about your diet and activity levels:

  • Weight Loss – Eat fewer calories than your TDEE. A safe reduction is about 500 calories per day, which can lead to around 0.5 kg (1 lb) of fat loss per week.
  • Weight Gain – Eat more calories than your TDEE, focusing on healthy foods to support muscle growth.
  • Weight Maintenance – Match your calorie intake to your TDEE.

Tips to Boost Your Metabolism

While you can't completely change your BMR, there are ways to support a healthier metabolism:

  • Build Muscle – Strength training increases lean muscle, which burns more calories.
  • Stay Active – Moving throughout the day keeps your energy burn higher.
  • Eat Enough Protein – Protein has a higher thermic effect, meaning your body uses more energy to digest it.
  • Stay Hydrated – Water helps with efficient calorie burning.
  • Sleep Well – Poor sleep can slow down your metabolism and affect hormones that control hunger.

Final Thoughts

Your Basal Metabolic Rate is more than just a number – it's the foundation of your body's energy needs. By understanding your BMR, you can make better decisions about your diet, workouts, and overall lifestyle.

Whether your goal is to lose fat, gain muscle, or simply maintain your current weight, knowing your BMR gives you the power to plan smarter and reach your goals faster.

Frequently Asked Questions

Find answers to common questions about BMR and how it affects your body and weight goals.

Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions like breathing, circulation, and cell production while at rest.

Knowing your BMR helps you determine how many calories you should consume to maintain, lose, or gain weight effectively.

No, BMR varies based on several factors including age, gender, weight, height, and muscle mass.

Yes, BMR generally decreases with age due to loss of muscle mass and hormonal changes.

You can check it periodically, especially if your weight, muscle mass, or activity level changes significantly.

Build more muscle, stay active, eat protein, get sleep, drink water, and avoid crash diets that slow your metabolism.

For men: BMR = 10 × weight (kg) + 6.25 × height (cm) – 5 × age + 5
For women: BMR = 10 × weight (kg) + 6.25 × height (cm) – 5 × age – 161
Or simply use our calculator above.

A "good" BMR depends on body type. Average is 1200–1800 calories/day but varies by person.

It's crucial for understanding your daily calorie needs and managing weight and diet plans effectively.

As you age, your BMR declines due to muscle loss and hormonal changes.

BMR determines calorie needs. To lose weight, eat fewer calories than your total daily expenditure (TDEE).

BMR is the base calories at rest. TDEE includes all daily activity and gives a more complete calorie requirement.