Basal Metabolic Rate (BMR)

You know that fat loss and muscle gain are about calories in versus calories out.

You know that it’s okay to eat your favorite foods in moderation as long as they fit within your calorie limits.

However, your problem is that you don’t know how many calories you need to maintain your weight.

You want to know the best way to estimate your maintenance calorie needs, so you can use that information to lose fatgain muscle, or be more flexible about your diet. That’s what you’re about to learn.

Let’s start by looking at the different ways your body burns calories.

The 5 Factors that Determine Your Maintenance Calories

  1. Your Basal Metabolic Rate (BMR)

This is roughly the number of calories you burn lying in bed, on an empty stomach, at a comfortable room temperature. Your BMR can change based on a number of factors, but it’s generally correlated with your lean body mass and to a lesser degree, your total body mass.1,2

The larger your total body mass, the higher your BMR. If a larger percentage of your body mass is muscle and other lean tissue, then you’ll burn even more calories.

Most moderately active people burn about 60-75% of their calories from their basal/resting metabolic rate.3-5

Your resting metabolic rate (RMR) is your BMR plus the number of calories you burn digesting food, the number of extra calories you burn after exercise, and other small bodily functions. We’ll use basal metabolic rate in this article, because we’ll be discussing the other components separately.

  1. Your Activity Levels & Excess Post-Exercise Oxygen Consumption

The biggest variable in your energy expenditure is how active you are — or your “thermic effect of activity” (TEA). The more you move, and the more intense your movements, the more calories you burn.

The problem is that the number of calories someone burns through formal exercise can range from zero to over six thousand calories per day.

If you’re moderately active, meaning you exercise around 30-60 minutes per day at a moderate to high intensity, the number of calories you burn through exercise will be around 15-30% above your resting metabolic rate.3 You’ll learn how to estimate the calorie needs of people with higher energy expenditures in a moment.

Excess post-exercise oxygen consumption (EPOC), aka “the after burn effect,” is the number of calories you burn after a workout that is due to the exercise. In most cases this isn’t significant,6 and you can think of EPOC as a bonus for pushing yourself a little harder rather than something you need to count.

  1. The Thermic Effect of Your Food (TEF)

This is the number of calories you burn digesting food. In most cases it will be around 10% if you eat a well-balanced mixed diet.7,8 If you eat 2,000 calories per day, you’ll burn about 200 calories digesting your food.

In most cases, the TEF of your diet is small enough that it’s not worth counting. It’s also hard to estimate your TEF since it changes based on what and how much you eat. For example, if you eat 500 calories less per day, you’re already burning 50 fewer calories through TEF. It’s easier to ignore TEF when calculating your maintenance calories.

  1. Your Non-Exercise Activity Thermogenesis (NEAT) & Non-Exercise Physical Activity (NEPA) Levels

“NEAT” represents the number of calories you burn through subconscious movement throughout the day.9“NEPA” is the number of calories you burn though non-formal, yet intentional movement. The former would be like fidgeting; the latter is like carrying groceries.

There are huge differences in people’s NEAT and NEPA levels, which makes them almost impossible to predict.10 However, a good ballpark estimate is around 200-400 calories per day for NEAT and NEPA. If you’re extremely hyperactive, have an active job, and/or have awesome genetics, you might burn closer to 600-800 calories per day through NEAT and NEPA.2,11

  1. The Adaptive Component

This represents how much your metabolic rate increases or decreases when you over- or under-eat.

In general, eating more increases your energy expenditure and eating less makes you burn fewer calories.12-14 This change is caused by subtle shifts in your resting metabolic rate, activity levels, and NEAT and NEPA levels.

The adaptive component isn’t something you can easily measure, and it’s not worth trying to calculate when estimating your calorie needs.

You should still keep this in mind, however, as you probably will need to adjust your calorie intake as you diet to account for these changes.

Now let’s look at some of the common formulas for estimating your basal metabolic rate — the first aspect of your energy expenditure.

How to Estimate Your Basal Metabolic Rate

Researchers have developed several formulas for estimating your basal and resting metabolic rates. These algorithms use indirect respirometry data as their standard.15 This means that researchers measure a bunch of people’s energy needs by analyzing the combination of gases expired in their breath, and then make formulas that account for different variables like gender, body mass, and body composition to help you estimate your calorie needs.

Let’s look at the most accurate equations for predicting your basal and resting metabolic rate. Then we’ll decide which one to use (if any). Here are the formulas we’ll examine:

  1. The Katch-McArdle Equation
  2. The Cunningham Formula
  3. The Mifflin-St Jeor Equation
  4. The Revised Harris-Benedict Equation
  5. The Owen Equation
  6. The WHO/FAO/UNU Equation
  7. The Aragon RMR Equation

A 2005 review found that the Mifflin-St Jeor equation was more accurate than the Harris-Benedict, Owen, and WHO/FAO/UNU equations.15 However, the Katch-McArdle is probably more accurate since it uses lean body mass instead of total body mass. Let’s start with that.

The Katch-McArdle Formula

BMR = 370 + (21.6 x Lean Body Mass (kg))

This is a newer formula that accounts for your lean body mass, which generally gives you a more accurate estimate of your basal metabolic rate (BMR).16 Since most of the difference between a man’s and woman’s BMR is due to their amounts of lean mass,1 this calculator works for both men and women. The downside is that you need to have a somewhat accurate estimate of your body composition.

You can use Leigh Peele’s free online calculator to perform the Katch-McArdle formula for you.

The Cunningham Formula

RMR = 500 + (22 x Lean Body Mass [LBM] in kg)

This is basically the same as the Katch-McArdle Formula, except it’s designed to predict your resting metabolic rate rather than your basal metabolic rate. This means it will usually be a little higher. As you’ll see, however, the difference is minor.

The Mifflin-St Jeor Equation

Men: (10 x weight in kg) + (6.25 x height in cm) – (4.92 x age) + 5

Women: (10 x weight in kg) + (6.25 x height in cm) – (4.92 x age) – 161

The is one of the newest and more accurate formulas.17 It tends to be about 10-20% more accurate than the other equations. It still has problems, however. It doesn’t account for body composition, which means it might not be as accurate for athletes. It also tends to underestimate the energy needs of obese people, although even then it’s fairly accurate.15

You can use Leigh Peele’s online calculator to do this formula for you.

The Revised Harris-Benedict Equation

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)

This method uses the your total body weight to calculate your RMR. It assumes you have a fairly average body composition, which means it can underestimate the energy needs of very muscular people and overestimate the needs of obese people.

This formula was revised in 1984, but both equations will give you almost the same result.18 I included the new one because I like to be complete.

There was also a study in 1999 by De Lorenzo et al. that developed a new formula for predicting the resting metabolic rate of male athletes.19 It was found to be more accurate than all of the other formulas tested:

RMR (kcal/d) = -857 + 9.0 (weight in kg) + 11.7 (height in cm)

Since this formula hasn’t been widely validated, and is still very similar to the others, you can forget about it for now.

If you’d like to use the Harris-Benedict Formula to estimate your resting metabolic rate, Leigh Peele has a calculator for that as well.

The Owen Equation

Men: 879 + (10.2 x weight in kg)

Women: 795 + (7.2 x weight in kg)

This is an older equation that is generally not as accurate as the others. It’s not worth using at this point.

The WHO/FAO/UNU Equation


18-30 year old RMR = (15.4 x weight in kg) – (27 x height in meters) + 717

31-60 year old RMR = (11.3 x weight in kg) + (16 x height in meters) + 901

>60 year old RMR = (8.8 x weight in kg) + (1128 x height in meters) – 1071


18-30 year old RMR = (13.3 x weight in kg) + (334 x height in meters) + 35

31-60 year old RMR = (8.7 x weight in kg) – (25 x height in meters) + 865

>60 year old RMR = (9.2 x weight in kg) + (637 x height in meters) – 302

This equation generally overestimates people’s BMR and is becoming less popular.20

There are two forms of this equation, one that only uses weight and one that uses your weight and height. I’ve only included the latter since you probably know how tall you are.

The Aragon BMR Equation

For Men and Women:

25.3 x lean body mass in kg

11.5 x lean body mass in pounds

I first saw this simple formula in Alan Aragon’s Research Review. It’s generally within about 5% of others and is much faster to use. Since there’s a margin of error with all of these equations, it makes sense to use the simplest one possible.

Comparing the Equations

Let’s see how these formulas compare to one another.

We’ll use “Don” as an example. Don is…

  • 70 kilograms (154 pounds).
  • 10% body fat.
  • 175 cm tall (5’9).
  • 25 years old.

Here are his BMR/RMR maintenance calorie estimates using these different formulas:

Katch-McArdle: 1731

Cunningham: 1886

Mifflin-St Jeor: 1676

Revised Harris-Benedict: 1760

Owen: 1593


Aragon: 1594

As you can see, all of these formulas are within 300 calories of each other. Since this is just an estimate, it makes the most sense to use Alan’s formula and save yourself a few minutes.

At this point you know how to estimate your basal metabolic rate. Now you need to calculate how many calories you burn through formal exercise and daily movement.

How to Estimate Your Total Energy Expenditure (TEE)

After you’ve estimated your RMR, you can apply one of these physical activity factors to estimate your total energy needs.

Sedentary (little or no exercise, desk job).

BMR x 1.2

Lightly Active (light exercise/sports 3-5 days/week).

BMR x 1.3-1.4

Moderately Active (moderate exercise/sports 3-5 days/week).

BMR x 1.5-1.6

Very Active (hard exercise/sports 6-7 days per week).

BMR x 1.7-1.8

Extremely Active (very hard daily exercise/sports and physical job or 2/day training).

BMR x 1.9-2.0

In most cases these formulas are already high enough to account for the thermic effect of food, and TEF is generally small enough that you don’t need to worry about it any more. However, if you’re a completist then here’s how to calculate that as well:

BMR x Activity Score X 1.1 = Total Energy Expenditure

The Alan Aragon TEE Equation

Alan Aragon has also developed an equation that you can use to predict your total energy needs that takes into account your activity levels. The same formula works for both men and women.

Here’s the equation in pounds.

Total Energy Expenditure = Target bodyweight in pounds x (8-10 or 9-11 + average total weekly training hours).

Here’s the equation in kilograms.

Total Energy Expenditure = Target bodyweight in kilograms x ((8-10 or 9-11 + average total weekly training hours) * 2.2)

You can also adjust this formula to take into account your gender and differences in daily activity levels.

If you’re a woman or someone with a sedentary lifestyle, use the “8-10” range.

If you’re a man or someone with a more active lifestyle, then use the “9-11” range.

This formula also accounts for the intensity of your exercise, including daily movement.

Woman or less active person:

8 = low intensity training.

9 = moderate intensity training.

10 = high intensity training.

Man or more active person:

9 = low intensity training.

10 = moderate intensity training.

11 = high intensity training.

Alan says this model tends to underestimate the calorie needs of sedentary people. If you don’t exercise much or at all, use the upper range of each multiplier. I’ve also found that even using the highest multipliers, this formula can still underestimate the energy needs of people doing a ton of training at higher intensities, like cyclists.

This formula is usually used for fat loss, but you can also use it to estimate how many calories you need to maintain or gain weight. Just plug in your target bodyweight, whether you want it to drop, stay the same, or increase, and you’re done.

The OCD Method

For the sake of completeness, here is how you could systematically calculate your energy expenditure based on each component.

  1. Estimate your BMR using The Aragon Equation.

25.3 x lean body mass in kg.

11.5 x lean body mass in lb.

  1. Estimate your NEAT and NEPA levels.

These numbers can be almost zero for one person and almost 1,000 calories for day for another, so these are only rough guidelines. Keep in mind this is only for calculating daily NEAT and NEPA, not formal exercise.

Sedentary: BMR x 1.1

Lightly Active: BMR x 1.15

Moderately Active: BMR x 1.2

Very Active: BMR x 1.25

Extremely Active: BMR x 1.3

  1. Calculate your activity energy expenditure with MET values.

Use this chart to find the “Metabolic Equivalent of Task, or “MET,” of your training.

Convert how many hours you train into a decimal. One hour of exercise is a “1” so half an hour of exercise is “0.5.”

Your Exercise Energy Expenditure = Weight in kilograms x MET value of exercise x duration of exercise in hours.

Add this value to your total energy needs.

  1. Calculate your thermic effect of food (TEF).

Multiply your total energy needs by 1.1.

Technically TEF drops and rises with your calorie intake, and it can also vary based on your food choices from about 5-15%.7 Ten percent is a good average guideline.

I don’t recommend using this method on an ongoing basis unless you have a spreadsheet set up to do the math for you. Even then it’s a little nuts. Here’s a simpler way to estimate your calorie needs.

The Simplest Way to Estimate Your Calorie Needs

  1. Estimate your calorie needs using Alan Aragon’s TEE Equation.


Target Calorie Intake = Target bodyweight in pounds x (8-10 or 9-11 + average total weekly training hours).


Target Calorie Intake = Target bodyweight in kilograms x ((8-10 or 9-11 + average total weekly training hours) * 2.2)

Woman or less active person:

8 = low intensity training.

9 = moderate intensity training.

10 = high intensity training.

Man or more active person:

9 = low intensity training.

10 = moderate intensity training.

11 = high intensity training.

  1. Track your food intake with a digital scale for 1-2 weeks.

Compare your recorded energy intake to your predicted calorie needs. If they’re significantly different, you may be under- or overestimating your calorie intake or the formula could have been inaccurate for you.

In either case, now you have a baseline from which to move forward. You don’t need to keep tracking your food intake with a scale forever, but doing so at first helps you get a much more accurate estimate of your calorie intake.

  1. Adjust based on your rate of weight loss or weight gain.

Reassess your calorie needs after tracking your food intake for 1-2 weeks.

Aren’t losing fat? Eat less.

Aren’t gaining muscle? Eat more.

Not maintaining? Adjust up or down based on whether you lost or gained weight.

Adjust your total energy intake up or down by about 10%. Then reassess after another 1-2 weeks.

Why Athletes and Bodybuilders May Want to Use a Different Method

If your energy expenditure changes significantly on a day-to-day basis, generally by more than about one thousand calories per day, finding your maintenance calorie intake can be a littler trickier.

Most of the previous formulas tend to underestimate the energy needs of people burning thousands of calories per day, like endurance athletes and many bodybuilders.

In some cases athletes might burn 5,000 calories one day and zero the next through formal exercise. If they ate the same amount every day, they might end up being in a severe deficit on some days and overeating on others. This often doesn’t cause any problems since athletes are generally good at eating enough to cover their energy needs by the end of the week.21,22

However, it’s often hard to know how much you should eat on a daily basis to recover from workouts and lose fat. This method is also useful if you’re using a more structured non-linear form of calorie cycling or are just more OCD. I’ve also found it to be more accurate with extremely hyper-active people who also exercise a lot.

  1. Estimate your non-exercise related energy needs.

This takes into account your BMR, TEF, NEAT, and NEPA.

Multiply your lean body mass by 31-35 in kilograms, or 14-16 calories per pound of lean body mass.

To adjust for NEAT and NEPA, I like to use the following multipliers. Values are in kilograms, pounds are in parenthesis.

31 (14) = sedentary/lethargic.

32 (14.5) = lightly active.

33 (15) = moderately active/somewhat fidgety.

34 (15.5) = very active/have trouble keeping still.

35 (16) = moves a lot/bouncing off the walls/people think you’re on meth.

Women should adjust down 1-2 levels since they generally burn fewer calories.

  1. Estimate the number of calories you burn through formal exercise.

Use this chart to find the “Metabolic Equivalent of Task” of your training.

Convert how many hours you train into a decimal. One hour of exercise is a “1” so half an hour of exercise is “0.5.”

Your Exercise Energy Expenditure = Weight in kilograms x MET value of exercise x duration of exercise in hours.

If you’re a cyclist who owns a power meter, you can also convert the kilojoules you produce during your workouts to calories. Most cyclists are around 19-23% efficient, depending on what data you’re using.23-26

Use this formula to convert the number of kilojoules you produced into how many calories you burned:

(Kilojoules / 4.184) / 0.19-0.23 = Calories burned during your bike ride.

Add this value to your non-exercise related energy needs.

  1. Adjust your calorie intake using the same method described above. 

If you’re gaining weight, you’re eating above maintenance. If you’re losing weight, you’re eating below maintenance.

Here’s an example of how “Don” would use this formula to calculate his maintenance calorie intake.

Don is 70 kilograms at 10% body fat, which means his lean body mass is 63 kilograms. He’s moderately active throughout the day and tends to be a little hyperactive. To find his non-exercise related energy needs, we would multiply his lean body mass by 33:

63 x 33 = 2079

Don lifts weights at a moderate to high intensity three times per week for about an hour per workout. These kinds of workouts have a MET value of around 6.

70 kilograms x 1 hour x 6 MET = 420 calories.

Don would then add his non-exercise and exercise related energy needs together:

2,079 + 420 = 2,499 calories per day.

Don’s estimated maintenance calorie intake:

Non-Training Days: 2,079

Training Days: 2,499

Average: 2,289

Don would then adjust his maintenance calories based on his food intake and bodyweight.

You Will Never Know Exactly How Many Calories You Burn — And You Don’t Need To

All of these equations are rough estimates.

None of these formulas are going to tell you exactly how many calories you burn on a daily basis,15,20,27,28and that’s fine.

All you need is a starting place from which to make adjustments. It’s not worth getting fancy metabolic testing or obsessing over the “perfect” formula for calculating your energy needs.

Metabolic rate formulas, and the advanced lab tests they’re based on, are both imperfect. As Leigh Peele says in her book Starve Mode, we are basically “using a guess to test a guess.”29 No matter how inaccurate these formulas are, however, they’re still better than having no idea how much you need to eat.

How Many Calories do You Need Per Day?

It depends, and it will change over time.

It’s generally a good idea to recalculate your energy needs at least every 4-8 weeks based on how much weight you’ve gained or lost and any changes in your activity levels.

If you accurately track your food intake, you can also use your food logs to estimate your energy needs based on whether or not you gain or lose weight relative to how much you’ve been eating.

If you’re an athlete who has large changes in energy expenditure on a daily basis, you might want to be more fastidious about calculating your energy needs more often.

After you’ve determined your maintenance calorie needs, you can adjust your food intake to lose fat, gain muscle, or set macronutrient targets so you can be more flexible about your food choices.



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