How to Calculate Your Basal Metabolic Rate (BMR)

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Your basal metabolic rate (BMR) is the minimum level of energy required to sustain vital functions such as breathing, digestion, and circulation—all of the bodily functions that happen beyond your control.

Your BMR is just one number you need to know if you're trying to lose weight. Losing weight is all about calories—the ones you burn and the ones you eat. All of the calories you burn in a day is known as your total daily energy expenditure (TDEE). Your BMR is one component, but other sources include non-exercise activity, exercise, and post-exercise oxygen consumption.

Measuring Your BMR

There are a large number of formulas out there for calculating your BMR, and, as always, you can easily use an online calculator to do the work for you. However, there is a common formula many experts use to estimate BMR, so get out your calculator and see what you can come up with.

Revised Harris-Benedict Formula

The BMR formulas are different for men and women and they've been revised since they were originally created. These are the revised Harris-Benedict BMR equations:

  • Male: (88.4 + 13.4 x weight in kilograms) + (4.8 x height in centimeters) – (5.68 x age)
  • Female: (447.6 + 9.25 x weight in kilograms) + (3.10 x height in centimeters) – (4.33 x age)

When using these formulas, your weight is in kilograms and your height is in centimeters and you will need to do a conversion if you normally use pounds and inches. For example, a 42-year-old male who is 5 feet 8 inches (173 centimeters) tall and weighs 200 pounds (91 kilograms) would use these numbers in the equation:

(88.4 + 13.4 x 91) + (4.8 x 173) - (5.68 x 42) = 1900 calories burned each day just to keep the body alive.

Online Calculators

You can also try several online tools that are available to calculate your BMR. These calculators usually involve inputting your sex, height, weight, and age to estimate your BMR. These calculators use the known formulas to make a guess based on your information.

Knowing your BMR can be helpful when you are trying to either maintain, lose, or gain weight. You can increase or decrease your calorie intake based on your results and goals.

Resting Metabolic Rate vs. Basal Metabolic Rate

Resting metabolic rate (RMR) and basal metabolic rate are two different measurements. These are often used interchangeably, but in the fitness world, your BMR is much more accurate. It's actually measured in a dark room after you wake up from eight hours of sleep and 12 hours of fasting to ensure that your digestive system isn't very active. The RMR measurement is much less restrictive.

Factors That Influence Your BMR

Some situations temporarily affect your BMR, such as eating spicy foods or going out in frigid weather. But there are only a few things that can affect your BMR for the long term.

  • Age: Your BMR will usually decrease as you age, which means many people may need to adjust their diet as they get older to avoid weight gain.
  • Weight: Heavier individuals will have a higher BMR.
  • Height: The taller you are, the more mass you are likely to have, influencing your BMR. Your height compared to your weight will also help determine how much fat-free vs. fat mass you have, impacting your BMR.
  • Sex: Men typically have a higher BMR than women due to increased muscle mass and bone density.
  • Genetics: Your genetics could influence your BMR. This is a factor that formulas cannot determine.
  • Body composition: Muscle mass expends more energy than fat mass. The higher your muscle mass, the higher your BMR can be, but this only accounts for a small amount of your energy expenditure.
  • Menopause: If you're going through it or have been through it, you already know your BMR usually goes down during this period of time, meaning you're burning fewer calories.
  • Weight trainingBuilding muscle is an excellent way to increase your BMR for the long term.
  • High-Intensity Interval Training: This form of exercise seems to beat weight training for raising your BMR.

Can You Change Your BMR

Changing body composition through weight training and high-intensity interval training can help. Your BMR will increase while you exercise and for a time afterward, but this effect won't last. Building muscle mass increases your BMR somewhat, but this effect is minimal compared to other factors. Some foods might have the ability to increase your BMR for a time, but these effects are also minimal and short-lived.

Your best bet is to increase your activity level, which increases your active metabolic rate (AMR). Find your AMR by multiplying your BMR by a specific number that represents various activity levels. This number ranges from 1.2 for being sedentary up to 1.9 for being very active.

  • Sedentary (little or no exercise): AMR = BMR x 1.2
  • Lightly active (exercise 1–3 days/week): AMR = BMR x 1.375
  • Moderately active (exercise 3–5 days/week): AMR = BMR x 1.55
  • Active (exercise 6–7 days/week): AMR = BMR x 1.725
  • Very active (hard exercise 6–7 days/week): AMR = BMR x 1.9

You can use this calculator to determine the approximate number of calories you burn each day.

Frequently Asked Questions

What Hormone is Most Responsible for Determining Basal Metabolic Rate?

The basal metabolic rate is mostly determined by the thyroid hormones T3 and T4, which respond to thyroid-stimulating hormone (TSH). T3 and T4 bind to mitochondria receptors, increasing adenosine triphosphate (ATP) production and increasing glucose use. ATP helps with the transportation and use of energy. These effects cause a higher cell metabolism.

A Word From Verywell

Understanding BMR can help you better understand your daily calorie needs, but keep in mind that it is only an estimate. If you are trying to change your body composition by losing or gaining weight, you should consider your BMR and activity levels. Certain factors that are out of your control will influence your BMR and calorie burn each day. You can make small adjustments based on your results to fine-tune your diet and exercise for your goals.

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Sabounchi NS, Rahmandad H, Ammerman A. Best-fitting prediction equations for basal metabolic rate: informing obesity interventions in diverse populationsInt J Obes (Lond). 2013;37(10):1364–1370. doi:10.1038/ijo.2012.218

  2. U.S. National Library of Medicine. Can You Boost Your Metabolism? May 26, 2020.

  3. Mullur R, Liu YY, Brent GA. Thyroid hormone regulation of metabolismPhysiol Rev. 2014;94(2):355-382. doi:10.1152/physrev.00030.2013

Additional Reading
  • Kelly MP. Resting Metabolic Rate: Best Ways to Measure It-And Raise It, Too. American Council on Exercise.

  • Strasser B, Schobersberger W. Evidence for Resistance Training as a Treatment Therapy in Obesity. Journal of Obesity. 2011;2011:482564.