BMR Calculator: Learn Your Basal Metabolic Rate

FDA-approved GLP-1s at their lowest prices. See if you qualify

Basal metabolic rate (BMR) is the number of calories your body burns just to stay alive — even if you remain in bed all day. It reflects the minimum amount of energy needed to power your most basic bodily functions, including:

Think of BMR as your body’s baseline energy requirement. It accounts for the largest portion of your total daily energy expenditure (TDEE), typically around 60%--70% in sedentary adults. That means even before you factor in exercise, walking, or digesting food, your body is already working hard behind the scenes.

Body composition (fat and muscle mass): Muscle tissue requires more energy than fat tissue. So, the more lean muscle mass you have, the higher your BMR.

Body size (height and weight): Larger bodies, whether due to greater height, weight, or both, require more energy to maintain basic functions.

Age: BMR naturally declines as you get older. This is mainly due to a gradual loss of muscle mass and changes in hormone levels that slow down metabolic activity.

Sex: On average, individuals assigned male at birth (typically, men) tend to have higher BMRs than those assigned female at birth (typically, women) because they generally have more muscle mass (thanks to higher testosterone levels) and lower body fat percentages.

Hormones: Hormone levels, especially thyroid hormones, play a significant role in regulating how quickly your body uses energy. Low thyroid activity, for example, can lower BMR, while high activity can raise it.

Genetics: Inherited traits can influence your metabolic rate, including how your body distributes muscle and fat or how efficiently it processes energy.

BMR is calculated using your age, sex, weight, and height. The most commonly used equations are the Harris-Benedict equation and the Mifflin-St Jeor equation . While both are widely accepted, the Mifflin-St Jeor equation is considered the more reliable and is used by most health professionals and research institutions today.

Females: (10 X weight [kg]) + (6.25 X height [cm]) – (5 X age [years]) – 161

Males: (10 X weight [kg]) + (6.25 X height [cm]) – (5 X age [years]) + 5

So, let’s say you’re a 35-year-old woman who weighs 160 pounds (72.7 kg) and is 5 feet 6 inches (167.6 cm) tall. To calculate your BMR, your equation should look like this:

(10 × 72.7) + (6.25 × 167.6) – (5 × 35) – 161 = 1,438.5 calories per day

There’s no single “normal” BMR that applies to everyone. That’s because your basal metabolic rate is unique to your body and shaped by individual factors like age, sex, weight, height, muscle mass, and hormone levels.

That said, scientists have been able to determine averages. According to the original paper that developed the Mifflin-St Jeor equation, the average male has a BMR of around 1,660 calories per day, and the average female has a BMR of around 1,400 calories per day. These numbers do not include the calories your body needs to turn food into energy and to perform physical activities.

Your BMR tells you how many calories your body burns each day at complete rest — in other words, just to keep your heart beating, lungs breathing, and cells functioning. This number is unique to your body and influenced by factors like age, sex, weight, height, and body mass.

A higher BMR generally means your body burns more calories at rest. This often reflects a higher proportion of lean muscle mass, a larger body size, or a younger age — all of which require more energy to keep things running.