BMR (Basal Metabolic Rate) Calculator

Basal Metabolic Rate (BMR) is the number of calories your body needs at complete rest to maintain vital functions like breathing, circulation, and cell production. A BMR calculator estimates this minimum energy requirement based on factors such as age, gender, weight, and height, providing a foundation for personalized nutrition and fitness plans.

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions while at rest. These include breathing, circulating blood, cell production, and body temperature regulation — even if you’re just lying down doing nothing.

Knowing your BMR helps you understand how many calories you burn without any activity. It’s a key factor in weight management, diet planning, and fitness tracking.

How This Calculator Helps

Our BMR Calculator helps you estimate your daily calorie needs using your:

  • Weight
  • Height (or height in feet/inches)
  • Age
  • Gender
  • Formula preference (e.g., Mifflin-St Jeor or Harris-Benedict)
  • Unit system (Metric or Imperial)

This tool is useful for:

  • Setting realistic weight loss or gain goals
  • Estimating how many calories you should consume daily
  • Understanding your metabolism better

How to Calculate BMR Manually

There are several formulas to calculate BMR. The most accurate and commonly used is the Mifflin-St Jeor Equation.

Mifflin-St Jeor Formula:

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

Example:
A 30-year-old man, 175 cm tall, 70 kg:
BMR = 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1648.75 calories/day

FAQ - BMR Calculator

Why is BMR important for weight loss?

BMR tells you how many calories your body burns without activity. If you eat fewer calories than your BMR + daily activity, you’ll lose weight. It sets the foundation for building your calorie deficit.

What's the difference between BMR and TDEE?

BMR is the calories your body needs at rest.
TDEE (Total Daily Energy Expenditure) includes activity (walking, exercising, etc.).
TDEE = BMR × Activity Level

Why are there different BMR formulas?

Some formulas are older or more tailored to certain body types. The Mifflin-St Jeor is more modern and accurate for most people. Our calculator defaults to this but may offer options like Harris-Benedict.

Does BMR change over time?

Yes. BMR naturally decreases with age, and it can also be affected by weight changes, muscle mass, and hormonal factors.

Should I use metric or imperial?

Use the unit system you’re most familiar with. Our calculator supports both metric (kg/cm) and imperial (lbs/inches), and converts as needed.