Sex Select your sex Male Female Select your biological sex as it affects calorie needs

Age (years) Enter your age in whole years (e.g., 25, 30, 45)

Weight (kg) Enter your body weight in kilograms (e.g., 65.5)

Height (cm) Enter your height in centimeters (e.g., 165, 170.5)

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Adult Male Average Adult Female Average

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This calculator provides estimates that may vary from clinical measurements. For accurate body composition analysis, consult a healthcare professional.

This BMR calculator uses the Mifflin-St Jeor equation and is designed for adults aged 18 and above. It may be used to estimate daily resting calorie needs for general wellness planning.

What Is Basal Metabolic Rate

Basal Metabolic Rate, or BMR, is the number of calories your body needs to stay alive while doing nothing at all. Think of it as the energy cost of just existing. It covers basic jobs like breathing, pumping blood, keeping your organs working, and maintaining body temperature. Even if you stayed in bed all day, your body would still burn this many calories. Knowing your BMR is often the first step in planning your daily food intake.

How Basal Metabolic Rate Is Calculated

Formula

This formula is called the Mifflin-St Jeor equation. It works by giving more calories to heavier and taller people, since bigger bodies need more energy to run. It reduces the calorie count as you get older, because metabolism tends to slow down with age. Men get a slightly higher base number than women, which accounts for the fact that men generally have more muscle mass. The formula adds up all these parts to give you one simple daily calorie number.

Why Basal Metabolic Rate Matters

Knowing your BMR gives you a starting point for understanding how many calories your body uses each day. It helps you make better choices about how much to eat based on your own body, not a random number from the internet.

Why Knowing Your Resting Calorie Needs Is Important for Weight Management

If you do not know your BMR, you may guess how many calories you need each day. Guessing too low may lead to eating very little food, which can leave you feeling tired and weak over time. Guessing too high may mean eating more than your body uses, which is associated with gradual weight gain. Using your BMR as a starting point may help you plan meals that better match what your body actually needs.

For Weight Loss

When the goal is weight loss, your BMR helps you find a safe starting point. Eating fewer calories than your total daily need (BMR plus activity calories) may support gradual weight loss. However, eating below your BMR for a long time is generally not recommended, as it may affect your energy levels and overall health. A slow and steady approach is commonly associated with more sustainable results.

For Weight Gain

If your goal is to gain weight or build muscle, your BMR tells you the minimum calories your body uses before adding any activity. You may consider eating more than your BMR plus activity calories to support weight gain. Adding protein-rich foods and strength training is often recommended alongside a higher calorie intake for better results.

For Different Age Groups

BMR naturally decreases as you get older. A person at age 50 may have a lower BMR than they did at age 25, even at the same weight and height. This means older adults may need fewer calories to maintain their weight. Younger adults and teens may find their BMR is higher, which is why they can often eat more without gaining weight. Adjusting food intake as you age is commonly recommended.

For Very Muscular or Very Overweight Individuals

The Mifflin-St Jeor formula was developed using a general population sample. People with very high muscle mass may find that the formula gives a lower estimate than their true calorie need, since muscle burns more calories than fat even at rest. Similarly, people with very high body weight may find the estimate less precise. In such cases, other methods like indirect calorimetry may provide more accurate readings, though they require clinical equipment.

BMR vs TDEE

BMR and TDEE (Total Daily Energy Expenditure) are often confused, but they are not the same thing. BMR is the calories you burn at complete rest. TDEE is your BMR multiplied by an activity factor, so it includes the extra calories you burn through daily movement and exercise. A common mistake is eating only BMR calories while being active, which may lead to a very large calorie deficit. Use BMR as your base, then add activity to find your TDEE for better meal planning.