Basal Metabolic Rate (BMR) Calculator (2024)

Table of Contents
  • BMR Calculator
  • What is BMR?
  • FAQ
  • Related Articles

Have you ever watched a teenager devour a towering double bacon cheeseburger, a plate full of fries, and a tall chocolate milkshake and wondered, "How do you eat like that and not gain weight?" Maybe you've started to notice that your pants have been feeling a bit snug around the waist, even though you're still eating the same healthy diet and following the same exercise routine of years past.

The answer, or at least a good explanation for this, is rooted in what's known as Basal Metabolic Rate, or BMR. BMR is responsible for approximately 60-70% of thetotal calories you burneach day.(1) It plays a key role in determining whether the body burns that double bacon cheeseburger for energy or stores it as fat.

Understanding your BMR may help you determine how best toeat for your body type, and using a BMR calculator is an easy way to find this number.

But better yet, understanding what a BMR calculator is actually measuring and knowing how to change your BMR might get you one step closer to your fitness goals.

These calculations are based on averages and are provided by Welltech Solutions. This Calculator is intended to by used by healthy, non-pregnant adults 19 and older. Athletes may require a higher caloric intake to maintain their current weight.

What is a BMR?

Basal Metabolic Rate, known as BMR, is the rate at which the body expends energy to maintain essential life functions while at complete rest. The majority of these essential functions continue mostly unnoticed—things like the heart beating, the lungs inhaling and exhaling air, the kidneys filtering waste, new cell creation, maintaining proper body temperature, and more. A BMR calculator measures the sum of kilocalories required to maintain these essential body functions. On average, this sum is approximately 60-70% of a person's total daily energy expenditure.

Because BMR measures these activities while at complete rest, a true calculation of BMR can only be done after a 12-hour fast and a good night's rest and in the absence of any physical activity or emotional excitement, as these factors can temporarily influence metabolic rate.

Factors that Affect BMR

Many factors affect BMR. Most notable are age, body shape, body composition, and hormones. Children and adolescents generally have a very high BMR because their bodies are in a constant state of growth, which requires a constant supply of food in order to gain energy. Remember that cheeseburger, fries, and milkshake that ‘magically disappears’ when a teenager eats it? This is why. As we age, our BMR slows as our body shifts from an anabolic (building) state to a catabolic (breaking-down) state.

Individuals with higher lean body mass—meaning more muscle—have a higher BMR than those without, as muscle requires significant energy to be maintained. Those with high body fat have a much lower BMR because fatty tissue requires very little energy to be maintained. For this reason, men tend to have higher BMR than women based on average body composition. (2)

The hormonethyroxine, produced in the thyroid, directly impacts BMR. Individuals with normal to elevated thyroxine levels (as found in hyperthyroidism) experience higher BMR than those with reduced thyroxine levels (as found in hypothyroidism).

Other factors affecting Basal Metabolic Rate include the total surface area of the body (higher surface area requires higher BMR to maintain body temperature), the presence of a fever or other physical stressors (which can raise BMR), fasting or starvation (both reduce BMR), smoking and caffeine (both increase BMR), sleep (reduces BMR), and emotional stress (increases BMR).

How to Calculate BMR

While you can calculate an estimated BMR using a BMR calculator (which utilizes the following formulas or accepted variations), calculations are only estimates. Your actual BMR is affected by many factors, as stated above.

  • Men: BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) - (5.677 x age in years)
  • Women: BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) - (4.330 x age in years)

Resting Metabolic Rate, or RMR, is the rate at which the body expends energy to maintain essential life functions while at rest, but can include the act of digestion or recent physical activity.(3) RMR measurements will be slightly higher than BMR measurements.

Total Metabolic Rate, or TMR, is the cumulative energy required to maintain essential life functions as well as all physical activity, everything from grocery shopping to a strenuous workout. Even slight increases in muscle activity can significantly raise the metabolic rate during exercise and several hours after.(4)

FAQs

  • What is a good BMR for my age?

    Because so many factors can affect your BMR—age, height, weight, body composition, hormones, stress levels, nutrition, caffeine intake, and more—it is difficult to set acceptable guidelines or standards for BMR measurements. On average, BMR decreases almost linearly with age due to changes in hormones and loss of lean muscle mass as strenuous physical activity tends to decline with age.(5)

    In order to offset or "fight back" against this decline in BMR, you must maintain healthy lean muscle mass. In other words, muscle is the key. While cardio exercise is good for your heart, it will not raise your BMR.(6) Instead, incorporate regular strength training into your routine to build and maintain muscle mass.

  • Are online BMR calculators accurate?

    Online BMR calculators provide a fairly accurate measure of BMR. While these BMR calculators do not include factors such as stress level, caffeine intake, nutrition, or hormone levels, they utilize measurable factors and basic BMR calculations to properly measure actual BMR. If you require an exact measurement, many doctor's offices, nutrition professionals, and even gyms can run tests using a special calorimetry device.

  • Do I need to know my BMR to lose weight?

    While it is not necessary to know your Basal Metabolic Rate to lose weight, it may be helpful. And knowing your TMR (total metabolic rate) is an even more helpful tool, as TMR measures the total kilocalories that your body burns on a daily basis. Remember that weight loss is not as simple as creating a calorie deficit, as many believe. Other factors, like hormones, can significantly affect your weight loss (or weight gain) goals.(7)

Basal Metabolic Rate (BMR) Calculator (1)

References

  1. Cleveland Clinic. (2021, August 30). Metabolism: What It Is, How It Works and Disorders. Cleveland Clinic.
  2. Buchholz, A. C., Rafii, M., & Pencharz, P. B. (2001). Is resting metabolic rate different between men and women? British Journal of Nutrition, 86(6), 641–646.
  3. Contributors, W. E. (n.d.-a). Differences Between BMR and RMR. WebMD. Retrieved December 5, 2022, from: https://www.webmd.com/fitness-exercise/difference-between-bmr-and-rmr
  4. Contributors, W. E. (n.d.-b). What Is Metabolism? WebMD. Retrieved December 5, 2022, from: https://www.google.com/url?q=https://www.webmd.com/fitness-exercise/what-is-metabolism
  5. H, S., & F, K. (1993, July 1). [Aging, Basal Metabolic Rate, and Nutrition]. Nihon Ronen Igakkai Zasshi. Japanese Journal of Geriatrics. https://pubmed.ncbi.nlm.nih.gov/8361073/
  6. Johns Hopkins Medicine. (2019). 7 Heart Benefits of Exercise. John Hopkins Medicine.
  7. Schwarz, N. A., Rigby, B. R., La Bounty, P., Shelmadine, B., & Bowden, R. G. (2011). A Review of Weight Control Strategies and Their Effects on the Regulation of Hormonal Balance. Journal of Nutrition and Metabolism, 2011.
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Basal Metabolic Rate (BMR) Calculator (2024)

FAQs

How do I calculate my BMR? ›

Male BMR = (9.99 × weight [kg]) + (6.25 × height [cm]) − (4.92 × age [years]) + 5. Female BMR = (9.99 × weight [kg]) + (6.25 × height [cm]) − (4.92 × age [years]) − 161.

What is a good basal metabolic rate BMR? ›

Factors such as genetics or even organ size – some people have large organs, which require more energy to function – account for these differences. Typically, BMR is between 1,000 and 2,000, meaning you need 1,000 to 2,000 calories to fuel basic functions.

Should I eat my BMR to lose weight? ›

Will You Lose Weight if You Eat Your BMR? Short answer: yes, but it's not sustainable. Remember, your BMR is just the number of calories your body burns at rest and does not account for the calories you need to walk, talk, exercise, etc.

How many calories should I eat a day if my BMR is 1400? ›

For example, if your BMR is 1,400 (the average for American women) and you are moderately active, your AMR would be 2,170 (1,400 x 1.55).

How do I adjust my BMR to lose weight? ›

To lose weight using your BMR:

The number should be somewhere between your BMR and the number of calories you need to maintain your current weight. As a guide, the average man needs about 2,500 calories and the average woman needs 2,000 calories a day to maintain their weight.

What is the official BMR formula? ›

Calculating the Harris-Benedict BMR
MenBMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
WomenBMR = (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

What is the correct BMR for my age? ›

How to Calculate your ideal BMR?
AgeMale (calories per hour)Female (calories per hour)
20–2939.537.0
30–3939.536.5
40–4938.536.5
50–5937.535.0
2 more rows
Jun 3, 2021

How many calories should I eat if my BMR is 1500? ›

You never want your total caloric intake to be less than your BMR. If your BMR is 1500 calories, you should never eat less than 1500 calories in a day. If you do—regardless of how much fat you have to lose—you encourage adaptive thermogenesis.

How many calories do 10,000 steps burn? ›

For more information, visit our medical review board. The idea of walking 10,000 steps a day, around 5 miles on average, is a popular fitness goal. Most people burn around 300 to 400 calories by walking 10,000 steps. Experts recommend gradually increasing steps, aiming for an extra 1,000 steps per day each week.

Is 1200 BMR too low? ›

Full stop. Research shows that the average woman aged 20 to 60 burns about 2,000 calories a day. So even if you're aiming for 1,200 as part of a weight loss regimen, you're going way too low — especially if you're active.

Do I need to eat 500 calories less than my BMR? ›

You should never eat less than your BMR as this is the basic number of calories your body needs to perform basic functions like breathing and digestion. Use your BMR to calculate your TDEE, and then you can eat less than your TDEE to lose weight.

What is a high BMR for a woman? ›

There isn't a "good" or "bad" BMR. “Each individual has a different BMR and cannot be compared to one another,” says Carmichael. What is considered to be “healthy” varies depending on the person and their goals. The average BMR for women is around 1400 kcal and about 1700 kcal for men, she says.

Why does my BMR go down as I lose weight? ›

On the other hand, if you eat and drink fewer calories than are burned through everyday activities (including exercise, rest, and sleep), you'll lose weight. Our bodies are also programmed to sense a lack of food as starvation. In response, our BMR slows down, which means fewer calories burned over time.

Is your BMR higher if you are overweight? ›

If you have a slow metabolism or slow BMR, your body needs fewer calories to keep it going. A fast metabolism does not necessarily lead to thinness. In fact, studies show that people with overweight/obesity often have fast metabolisms. Their bodies need more energy to keep basic body functions going.

Why is my BMR so low female? ›

Factors that affect our BMR

Amount of body fat – fat cells are 'sluggish' and burn far fewer kilojoules than most other tissues and organs of the body. Crash dieting, starving or fasting – eating too few kilojoules encourages the body to slow the metabolism to conserve energy.

What is the formula for resting metabolic rate? ›

RMR = (9.99 X actual weight*)+ (6.25 X height*) – (4.92 X age) – 161*use weight in kilograms (kilogram), height in centimeters (cm). SedentaryLight physical activity associated with typical day-to-day life.

How do I calculate my calorie deficit to lose weight? ›

To perform a manual calculation, moderately active people can multiply their current body weight by 15 to estimate how many calories they would need each day. Anything less than this is a deficit.

How do you calculate BMR activity? ›

How do I calculate my BMR? To calculate your BMR, you would usually use the Harris-Benedict equation: For women, it's: BMR = 655.1 + (9.563 × weight in kg) + (1.850 × height in cm) - (4.676 × age) . For men, the formula is: BMR = 66.5 + (13.75 × weight in kg) + (5.003 × height in cm) - (6.75 × age) .

How many calories do I naturally burn a day? ›

How many calories do you naturally burn in a day? That depends on your age, sex, height, and weight. It can approximately range from 2,000 to 2,450 calories for men and 1,600-1,950 for women (not including calories burned from exercise).

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