BMR Calculator

This calculator estimates basal metabolic rate using body size, age, and sex. BMR represents the calories your body would use if you were resting all day.

It also estimates calorie levels for different activity patterns by multiplying BMR by common activity factors. These results are often used as a starting point for calorie planning.

This BMR calculator uses body weight, height, age, and sex to estimate basal metabolic rate. The result is an estimate of how many calories your body uses each day at complete rest.

After calculating BMR, the tool applies common activity multipliers to estimate maintenance calories for sedentary, lightly active, moderately active, active, and very active lifestyles.

BMR stands for basal metabolic rate. It is the number of calories your body needs each day just to stay alive at rest. These calories support basic functions such as breathing, circulation, cell repair, and body temperature regulation.

A BMR calculator helps estimate your resting calorie needs using body size, age, and sex. Many people use BMR as a starting point when planning calorie intake for weight loss, maintenance, or muscle gain.

Enter your sex, age, height, and weight to estimate your basal metabolic rate. The calculator then shows your BMR along with estimated daily calorie needs at different activity levels.

In practical terms, BMR is not usually the number of calories you should eat. Most people need more than their BMR because they walk, work, exercise, and perform normal daily activities. That is why maintenance calorie estimates are also shown.

BMR is your resting energy requirement. TDEE, or total daily energy expenditure, is your estimated calorie burn across a full day after activity is added. Maintenance calories are often used to describe the daily calorie intake that would keep your body weight about the same.

In many health calculators, maintenance calories are estimated by multiplying BMR by an activity factor. This gives a more realistic daily target than BMR alone for most people.

If your goal is weight loss, people often compare their estimated maintenance calories with a moderate calorie deficit. If the goal is weight maintenance, the maintenance estimate becomes the reference point. If the goal is muscle gain or body weight increase, some people use a moderate calorie surplus above maintenance.

BMR itself is usually the baseline, not the final calorie target. The more useful planning number is often the daily calorie estimate that matches your typical activity level.

Several factors affect basal metabolic rate, including body weight, height, age, sex, and body composition. Larger bodies generally use more energy at rest. Younger people and those with more lean body mass often have higher resting energy needs as well.

BMR calculators are useful estimates, but they do not account for every individual difference. Real calorie needs can vary because of genetics, hormones, health status, daily movement, and muscle mass.

Suppose someone enters their age, sex, height, and weight into the calculator and gets a BMR result of 1699 kcal/day. That means their body is estimated to use about 1699 calories each day at complete rest.

If that same person is moderately active, their estimated daily maintenance calories might be around 2633 kcal/day. That activity-based estimate is usually more useful for planning daily eating than BMR alone.