If you're trying to lose, gain, or simply maintain weight, calculating your Basal Metabolic Rate, also known as your Basal Metabolic Rate (BMR) in English, is a good idea. Basal metabolism is the amount of energy your body uses when it's at full rest – in simple terms, the energy your organs use and sustain your life on a daily basis regardless of any physical activity. Your basal metabolic rate is affected by many variables – gender, age, height and weight are the most important, but your body fat percentage, diet, and regular exercise also play an important role. Please continue reading for an easy way to calculate your basal metabolic rate for all genders.
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Method 1 of 2: Calculating Basal Metabolic Rate in Men
Step 1. Measure your height in centimeters
In general, the bigger you are, the higher your basal metabolic rate. When other aspects of the body are considered equal, a taller man will have more body tissue in his body than a shorter man; this results in taller men needing more energy each day just to live. If you are unsure of your exact height, start by measuring it appropriately. Use centimeters – the basal metabolic rate should be calculated in metric units.
- Stand with your back to the wall, your heels against the wall and your body in an upright position. Ask someone to help you mark the height of your head. Then calculate the height of the mark that was made earlier from the floor in an upright position using a measuring tape to find out your height.
- If you know your height in inches, you can multiply your height by a multiplier of 2.54 to find your height in centimeters.
Step 2. Weigh your weight in kilograms
If you haven't weighed yourself in a long time, then weigh again. In general, the higher you are, the more energy your body will need each day. Weighing your weight is also a good idea if you intend to gain or lose weight because you can record it as a starting point for your efforts.
- If you know your weight in pounds, you can multiply your weight by a multiplier of 0.454 to find your weight in kilograms.
- If you are planning to gain or lose weight, keep in mind that your weight can change by about 2 kg per day based on what you eat or drink, or because you poop, etc. If you are trying to change your weight, weigh yourself once a week on the same day and time wearing the same clothes.
Step 3. Use the formula for calculating the basal metabolic rate for men
For men, the formula for calculating the basal metabolic rate is: BMR = 66 + (13.8 x weight in kg) + (5 x height in cm) – (6.8 x age in years). This simple formula takes into account your height, weight, age, as well as gender. Basal metabolic rate increases with height and weight but decreases with age.
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The value in the calculation of the basal metabolic rate uses units of kilocalories per day.
In everyday speech, kilocalories are often referred to as "calories" - for example in the nutrition information section of food packages.
Step 4. Know other factors that can affect the basal metabolic rate
The basal metabolic rate calculation formula isn't perfect – it's just a simple way to estimate your basal metabolic rate. Your basal metabolic rate may change based on several other factors such as:
- muscle mass. A lean but muscular body will have a higher basal metabolic rate than a fat body. An Olympic swimmer who weighs 91 kg and has near zero body fat will have a higher basal metabolic rate than another man of the same weight but more body fat.
- Body growth. People who are growing (such as during puberty) will have a higher basal metabolic rate, as will people who are healing after an injury.
- body temperature. High body temperature (such as when you have a fever) can increase the basal metabolic rate.
- Dietary habit. Fasting or drastically reducing food portions can reduce your body's basal metabolic rate as your body has to try to keep going on a more limited source of energy.
- Descendants. Some people can inherit their basal metabolic rate from their parents – if you've ever met a person who can eat continuously without getting fat, you've met someone who has inherited a naturally high basal metabolic rate.
Method 2 of 2: Calculating Basal Metabolic Rate in Women
Step 1. Measure your height and weight
As in men, the basal metabolic rate can vary in women based on height and weight. For an accurate measurement of your basal metabolic rate, measure your height and weight accurately. Use metric units – centimeters for height and kilograms for weight – because calculating basal metabolic rate uses metric units of measurement.
- To convert your height from inches to centimeters, multiply by a multiplier of 2.54. To convert your weight from pounds to kilograms, multiply by a multiplier of 0.454.
- If you are trying to lose or gain weight, always remember to weigh yourself at least once a week, at the same time and day. Your weight can change about 2 kg just because of your daily activities.
Step 2. Use the formula for calculating the basal metabolic rate for women
Since women generally (but not always) have a lower base body mass (calculated by subtracting body fat mass from total body mass) than men, women will have a lower basal metabolic rate. The formula for calculating the basal metabolic rate in women also takes this into account – it multiplies height and weight by the smaller value. However, the metabolism in women decreases not as fast as in men in the aging process, therefore the age multiplier is reduced. For women, the formula for calculating the basal metabolic rate is as follows: BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in years).
And as usual, the value of the results of this calculation is expressed in units of "kcals (kilocalories) per day."
Step 3. Recognize that pregnancy affects the basal metabolic rate
As in men, diet, growth, body temperature, muscle mass, and heredity can affect the basal metabolic rate in women. However, in women, pregnancy can significantly affect the basal metabolic rate. Pregnant or lactating women will have a higher basal metabolic rate than normal women. The process of nourishing the fetus (and subsequently producing breast milk) requires more energy from the body – if you have ever seen and noticed that a pregnant woman's appetite increases, then you have seen this happen for yourself.
Tips
- Once you know your basal metabolic rate, you can multiply it by your activity rate multiplier to get Total Daily Energy Expenditure, which estimates the total number of calories you use in one day. The multiplier used for people who are more sedentary is 1.2, people who do light activities (light exercise 1 to 3 times a week) are 1,375, people who are moderately active (exercise 3 to 5 times per week) are 1, 55, people who are very active (exercise hard 6 to 7 times a week) are 1,725, and people who are very very active (exercise hard every day or people who exercise more than once per day) are 1.9.
- Once you know your body composition, you can use your base body mass to accurately calculate your basal metabolic rate. Body composition is a calculation to find out how much of your body is fat. Any body weight that is not fat is the base weight. This calculation applies to all genders. BMR = 370 + (21.6 x base weight in kg).
