Whether you’re trying to manage your weight or simply want to maintain a healthier lifestyle, knowing your Basal Metabolic Rate is important. Your BMR is determined by several factors. That’s why it varies so much for person to person. When you know your BMR and the factors that determine it, you can adjust your lifestyle to suit your body’s needs.

What is Basal Metabolic Rate?

First, let’s take a look at what BMR means. Simply put, the Basal Metabolic Rate is how many calories your body consumes to keep it functioning when you’ve been at rest for about 12 hours. Keep in mind that when you’re at rest, your body continues to consume calories for basic bodily functions like breathing, blood pressure, brain functions, and maintaining your body temperature. Your BMR makes up about 60% of the calories you need every day, while the rest of the calories you require are for more active pursuits.

For those who want to lose weight, knowing your BMR is important. This gives you a baseline for how many calories your body burns when you’re at rest. When you know your baseline, you can take steps to increase your BMR. The higher your BMR, the more calories your body burns even when you’re not doing anything. To do this, you must also consider the factors that determine your BMR.

What Factors Determine a Person’s BMR?

Below are the many factors that determine your BMR:

Body Size

The size of your body impacts your BMR because the bigger you are, the more calories your body needs to keep everything in order. People who are taller or more heavy-set have a larger surface area, all of which require calories to maintain. However, while size matters, the composition of your overall body mass matters just as much.

Muscle Mass

While people who are taller or heavier generally have a higher BMR, their body composition also has a huge effect. Lean muscles require more calories to maintain, so more lean muscle means a higher BMR. As such, if people have more fat tissue in their body, they have a lower BMR.


As you grow older, you steadily lose lean muscle mass. As mentioned above, the less muscle mass, the lower the BMR. Keep in mind that you can take steps to avoid this as you grow older. Strength training and maintaining an active lifestyle help to tone your muscles, thus preventing you from losing muscle mass.


Men and women have different BMRs. Women are biologically predisposed to store more body fat to maintain their hormones. Because of this, they generally have less muscle mass compared to men. For women, the average BMR is around 1400 calories a day. For men, on the other hand, it’s a little more than 1600 a day.

Overall Health

Illnesses, whether long-term or acute, also have a huge effect on a person’s BMR. People who have a fever or are in pain tend to consume more calories because the body works harder to keep the rest of the body functioning. The same is true for people who are fighting off infections and other diseases. Likewise, injuries also require the body to spend more energy and consume more calories to heal faster.

Thyroid Function

The thyroid gland produces thyroxine to maintain bodily functions such as regulating the body’s temperature, heart rate, blood pressure, and metabolism. Thyroid function can vary throughout one’s lifetime. For instance, women experiencing menopause often have an under-functioning thyroid, which affects their BMR. People who have thyroid problems may likewise experience increased or decreased metabolism.


External factors can also affect your BMR, the most important of which is the climate. People who live in hotter areas usually have a higher BMR than those who live in colder areas. The body requires more energy to keep itself cool and thus needs more calories.

However, those who are exposed to colder climates can also experience an increase in BMR. This happens when their clothing and body fat content isn’t enough to keep the body warm. So their bodies spend more energy to work against the cold.

Calculating Your Basal Metabolic Rate

A BMR calculator can help you determine your BMR. It’s a simple tool to give you an estimation of your BMR. All you need to do is input your weight, height, and age. The calculator then gives you your BMR based on your gender, which you can then use to see if you’re within the healthy range.

Keep in mind that this BMR calculator doesn’t factor in your overall health, thyroid function, or the climate in the city you live in. Its purpose is to give you an ideaabout your BMR.

When you know the factors that affect your Basal Metabolic Rate, you can use it to learn both your BMR and any changes you need to make in your lifestyle.