Once you measure your RMR, the answer will give you the approximate number of calories your body burns daily while at rest. There are many ways to calculate RMR and BMR. The simplest is by plugging numbers into a calculation that takes your height, weight, age, and gender into account, but the accuracy of this method is questionable.

A lab-based test called indirect calorimetry is the most reliable method to measure RMR, but this method is expensive and time-consuming. If you enjoy math, you can also calculate BMR on your own. The year-old Harris-Benedict Equation is still used to help estimate BMR. You can also use this equation online at Cornell University.

Just how accurate is the Harris-Benedict equation? It's said to have an accuracy of no more than 70 percent, which means it can lead to major errors in estimating your true calorie needs.

Of the equations that exist for measuring metabolic rate, the Harris-Benedict is still the best choice no equation is more accurate than 70 percent. You can use an online calculator to measure your RMR as long as you know your height and weight. You can use these links to find an online RMR calculator:.

Some medical facilities offer indirect calorimetry to provide you with a metabolic rate that's more reliable than using a calculation. The test is non-invasive and usually takes about an hour.

For the test, you will wear a mask for a short period of time around 15 minutes while resting. The mask measures the exchange of gasses to determine the number of calories you burn when your body is at complete rest. The test is most often used in critically ill patients to determine their nutritional needs, but some non-medical settings like gyms may also offer it.

There is no single RMR value that is appropriate for all adults. But some people still like to know what the average RMR is for fellow humans. When the Harris-Benedict equation was set in the s, the average RMR for women was calories per day and just over calories for men.

A more recent reference found that RMR in sedentary adults can range from less than to more than calories per day in both men and women. So, there's a huge range for what's deemed an 'average' RMR.

And remember, these RMR estimates are the calorie levels at rest, which does not take activity levels into account. Your weight, height, age and gender all are used to calculate your RMR, so these factors can impact the results. Race, diet, and activity level can all have an impact on your RMR or BMR too.

Interestingly, about 80 percent of the variability can be explained by how much lean and fat tissue a person has. You can add one more layer to your results in the Harris-Benedict calculation above , which accounts for your total daily energy expenditure TDEE , including activity.

There are five possible numbers, based on how active you are:. Some other factors that can be involved in determining RMR include:. RMR calculations can be used as a very basic tool to estimate your calorie needs, but remember that calculations like the Harris-Benedict are only about 70 percent accurate.

That means it would be very easy to overestimate or underestimate your daily calorie needs by using this calculation.

It's not a very reliable method to determine calorie needs. A lab test such as indirect calorimetry is a more reliable measure, but it's also a costly method and is still a 'best guess' at your actual calorie needs.

Estimating your calorie needs using a calculation that takes your actively level into account is a quick way to get a vague estimate of your calorie needs. But remember, the number is not completely reliable and is just a rough estimate.

Meticulously counting every calorie you eat or burn off with exercise based on a calculation is an exercise in futility, because it's all based on estimates. A better idea? Listen to your hunger cues. Eat when you feel hungry, and stop when you feel full. Enjoy movement and stay active.

And put the calculator away. RMR in sedentary adults can range from less than to more than calories per day.

BMR is the amount of energy used when you're lying still and awake. RMR is similar but can include some low-effort tasks.

BMR is measured when fully at rest, while RMR can have a small bit of movement. In an ideal world, RMR calculations would be percent accurate and would let us know exactly how many calories our bodies need each day. That would allow us to cut calories for weight loss. DeBerardinis RJ, Thompson CB.

Cellular metabolism and disease: what do metabolic outliers teach us? Oxford Reference. Metabolic rate. Jensen, M. Goldman Cecil Medicine 26th Edition.

Obesity chapter. McMurray RG, Soares J, Caspersen CJ, McCurdy T. Examining variations of resting metabolic rate of adults: a public health perspective.

Med Sci Sports Exerc. Bendavid I, Lobo DN, Barazzoni R, et al. The centenary of the Harris-Benedict equations: How to assess energy requirements best? Recommendations from the ESPEN expert group.

Clin Nutr. Cioffi I, Marra M, Pasanisi F, Scalfi L. Prediction of resting energy expenditure in healthy older adults: A systematic review. Mtaweh H, Tuira L, Floh AA, Parshuram CS.

Indirect calorimetry: history, technology, and application. Front Pediatr. Gupta RD, Ramachandran R, Venkatesan P, Anoop S, Joseph M, Thomas N. Indirect calorimetry: from bench to bedside. Indian J Endocrinol Metab. Blunt K, Dye M. Basal metabolism of normal women. J Biol Chem.

Global RxPh. Harris Benedict Basal Metabolic Rate Calculator. Chung N, Park MY, Kim J, et al. The body reacts to weight loss as if it is starving and, in response, slows its metabolism. When your metabolism slows, you burn fewer calories — even at rest.

When you burn fewer calories, two things can happen if you continue eating fewer calories:. If you then increase your calorie consumption, you may actually gain weight more quickly than you had in the past. The solution is to increase your physical activity, because doing so will counteract the metabolic slowdown caused by reducing calories.

Regular exercise increases the amount of energy you burn while you are exercising. But it also boosts your resting energy expenditure — the rate at which you burn calories when the workout is over and you are resting. Resting energy expenditure remains elevated as long as you exercise at least three days a week on a regular basis.

The kinds of vigorous activity that can stimulate your metabolism include walking briskly for two miles or riding a bike uphill.

Even small, incremental amounts of energy expenditure, like standing up instead of sitting down, can add up. Another benefit of regular physical activity of any sort is that it temporarily curbs your appetite.

Of course, many people joke that after a workout they feel extremely hungry — and promptly indulge in a snack. But because exercise raises resting energy expenditure, people continue to burn calories at a relatively high rate.

So a moderate snack after exercising does not erase the benefits of exercise in helping people control their weight. As a service to our readers, Harvard Health Publishing provides access to our library of archived content.

Please note the date of last review or update on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

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