How to Calculate Calorie Needs Accurately

calcuating tdee

Table of Contents

As discussed in the previous two articles, counting calories and how calories affect your body composition, the next logical step is to figure out how many calories you need per day. This is also called daily caloric requirements.

Quick equation:

When calories in are the same as calories out = calorie balance (maintenance)

Your calorie maintenance requirements are what we will find out/estimate in this article. Before we can adjust your caloric intake to your goal, whether it’s to build muscle, lose weight, lose fat, or recomp, we must first calculate how many calories your body needs to perform its functions. You are probably not just breathing and sitting all day long, so those “extra” activities you perform daily will also affect your caloric requirements since they utilize some energy as well.

For instance, if you are sedentary and need 2000 calories to maintain your weight, that will be your daily caloric requirement. Since you most likely have a job, walk your dog, cook, and train (hopefully) the number of calories you burn a day will be 2000 calories (just from existing) plus whatever number of calories you burn because of those additional activities. So, it would be 2000 + whatever = your daily caloric requirement.

Don’t worry, we will get to it in a second.

Quick reminders:

Caloric surplus (when you eat MORE calories than your body burns) = gain muscle, fat or both.
Caloric deficit (when you eat LESS calories than your body burns) = lose fat, muscle or both.
Caloric balance (when you eat EXACTLY the same number of calories your body burns) = no change in weight. But your body composition changes depending on whether you are training or not.

So, how do we calculate our maintenance calories?

In the “basics of an effective diet” article, I asked you to write down some information about yourself. Well, today is the day you use that data you jotted down. Those numbers will be used to calculate your daily caloric requirements.

We are all different and have different lives, therefore, there is no way we would all have the same number of maintenance calories. Instead, your daily caloric requirements are determined by many factors such as:

Your weight
Activity level (how active are you on a daily basis?)
Stress levels
Any allergens or health problems
Metabolism (how fast is your metabolism? Slow as a turtle? Or, fast as a horse?)
NEAT (Non-Exercise Activity Thermogenesis)

And for these reasons, there is no way two people would have the same exact number of maintenance calories even if they have the same weight, height, age and gender. Your diet/energy requirements are only exclusive to you and you alone.

NOTE: It is almost impossible to accurately calculate the exact number of calories you need to maintain your weight (maintenance calories). Maintenance calories is a moving target. Fortunately, we can calculate a close-enough estimate and still get the job done. If you are interested in measuring your basal metabolic rate (BMR) as accurately as possible, stop by your local fitness center and get a direct or an indirect calorimetry test.Besides being inconvenient, calorimetry tests cost a bit of money as well. Fortunately, you don’t need to go through a calorimetry test to get a good estimate of your BMR.

There are 3 main methods you can use to calculate your daily caloric requirements, and those are:

  1. Mifflin-St Jeor Equation (a simple yet effective maintenance calculator). However, it has its flaws.
  2. Real world numbers. This is derived from what hundreds of thousands of trainees have played around with and its pretty accurate.
  3. Trial & Error 

Let’s discuss each one individually.

#1) Daily caloric requirements calculator

This is by the far the easiest way to calculate how many calories you need per day. You just plug in some numbers, click calculate and voila, you get how many calories you need per day to maintain your weight.
This calculator is based on a complex equation that was put together by Mifflin st-Jeor, a well-respected researcher. He came up with equation during a clinical study in which he was trying to figure out energy requirements for different individuals. This equation is well-accepted in the fitness realm and is a bit more accurate than the other two calorie requirement methods because it takes into account different factors, including activity level, age, gender and height. 

Major Drawback of Mifflin st-Jeor

The main problem with Mifflin st-Jeor equation (and most other ones) is that it can significantly overestimate someone’s BMR and thus how many calories that person needs to eat. However, worry not, there’s a simple way to work around this issue.

Simply plug in your data into the calculator below and click “submit”. An external window will pop up showing you an accurate estimate of your daily caloric requirements in relation to different activity levels.

Here is an example:

I plugged in the following information into the calculator (gender, height, age and weight) and clicked submit. This is the window that popped up:
calorie calculator

The calculator then gave me estimated numbers corresponding with different activity levels. If you are sedentary (couch potato) you would then need to consume 1970 calories per day to maintain your weight.

If you are a bit more active (lightly active), you would then need 2258 calories per day to maintain your current weight.

And so on and so forth.

While this method is convenient and somewhat reliable, the main issue is that you can easily overestimate your activity level which could throw off your daily caloric requirements by several hundred calories as you can see in the picture above. And those extra several hundred calories are EXTREMELY important! They can make or break your success and depending on whether you underestimate or overestimate your caloric requirements, you can create a large caloric surplus or deficit and sabotage your progress. Be very careful when using this equation, or any other equation, or you risk eating more than you should. Outcome? You may get fat like me, or lose too much weught too fast and consequently lose too much muscle (been there as well).

If you Google “activity levels” you will get different descriptions from different websites. Some are reliable, some can be a bit confusing. Such activity level descriptions often look something like this:

Sedentary Regular daily activities such as: eating, cooking, walking the dog, shopping, watering plants…etc.
Desk job where you don’t do much activity.
No daily exercise (weights, jogging, walking…etc.)
Lightly Active Daily activities: eating, walking the dog, shopping…etc.
A job that requires you to stand on your feet most of the time such as: teacher, doctor, sales associate…etc.
Perform some type of physical exercise daily but not vigorous exercise. This can be something like 30 minutes of daily walking at moderate pace (3-4 MPH).
This type of exercise could be described as light exercise 1 to 3 times per week.
So, you perform light exercise for about 1-3 hours every week.
Moderately Active Daily activities: eating, walking the dog, shopping, gardening…etc.
A job that requires you to stand on your feet most of the time such as: teacher, doctor, sales associate, security guard…etc.
Daily moderate exercise 3 to 5 times per week.
By the end of week, you do about 3 to 5 hours of moderate exercise.
Very Active Daily activities: cooking, walking the dog, shopping, gardening, hanging out with friends…etc.
A somewhat physically demanding job such as: waiter, mailman, warehouse worker where you lift things up and put them down!
Daily heavy exercise performed for 1-1.5 hours every day, 6 to 7 times per week.
This adds up to about 5-9 hours of serious exercise per week.
Extremely Active Daily activities: existing, cooking, walking the dog, shopping, gardening, hanging out with friends…etc.
A very physically demanding job such as a blacksmith, construction worker, delivery boy…etc.
Super strenuous exercise performed for 1.5-2 hours every day, 6 to 7 times per week. Or perhaps you work out twice a day! You would fit hit as well.
Total hours of strenuous exercise performed per week = 10-20 hours.

NOTE: The descriptions above are based on individuals of average weight ~ 140-170 lbs. and average age. Because obviously, those factors also affect how much energy your body uses. For instance, an individual who weighs 200 pounds and lightly active lifestyle will require more calories than an individual who weighs 150 pounds and has the same activity level.

The Solution

Since maintenance calorie equations tend to overestimate one’s caloric requirements, the only way to get around this major drawback is to avoid factoring in activity level. Realistically, the number of required calories per day should consider the following factors:

Resting metabolic rate (RMR) 
Amount of lean body mass you have 
Energy burned during food digestion – TEF (thermic effect of food)
Non-Exercise Activity Thermogenesis (NEAT)
Exercise Related Activity Thermogenesis (ERAT)

The most reliable equation that takes all those factors into consideration is the Cunningham equation. It is, by far, the most accurate formula to determine one’s caloric requirements. There is one tiny problem though; miscalculating your caloric requirements through the Cunningham equation is also easy!

Here is the solution; DO NOT factor in your activity level when using the calculator above! In other words, just use your basal metabolic rate (BMR). In the example above, my hypothetical person’s BMR was 1642 cals per day. Just use this number.

Underestimating your maintenance calories is much better than overeastimating it, trust me. Why? Because even if 1642 calories are lower than the real number of calories required, my hypothetical person can always increase his caloric intake. However, overestimating your caloric requirements may put you in a large surplus and cause you to gain weight rapidly. So, after you plug in your data, just use the BMR the calculator gives you.

Other equations worth mentioning:
Katch Mcardle
Cunningham’s equation (Most accurate)
Owen’s equation
Moving on, perhaps you would like to use/learn another method to estimate your daily caloric requirements.

#2) Real world numbers. 10-12 calories per pound of bodyweight

These numbers are not just magical numbers that came out of nowhere, but they came from the experience of thousands of trainees and fitness experts who came to the same conclusion.
Simply, take your current weight in pounds and multiply that number by any number between 10-12 and you will get a good estimate of your resting metabolic rate (RMR).

Which number is right for you?

If you are a female, somewhat old, not that physically active or feel like you have a slow metabolism, you will be better off sticking with the bottom end of this range. So, 10-11 per pound of body weight.
If you are a young male or feel like you have a fast metabolism – we hate you -, and can eat everything in sight and not gain a single pound, you are better off using the higher end of this range. So, 11-12 calories per pounds of body weight.

Some individuals have certain medical conditions that can affect their metabolic rate. So, for example, if you have a slow thyroid/metabolism, use the lower end of the spectrum. And vice versa.

For most people, the best approach will be to pick a number between 10-12 and multiply that by your body weight in pounds. Or, you can use every single number, add them up and take the average.

Quick example:

A 25-year-old healthy male who is lightly active, has a normal metabolism and weighs 160 pounds would multiply; 160 *11 = 1760. Thus, this individual will have a close estimate of his resting metabolic rate (RMR) and that would be 1760 calories / day to maintain his weight!

The problem with this method is that it has the potential of giving a false estimate due to user error. One might “feel” that his metabolic rate is slow and choose 10 calories per pound of body weight while he may have a perfectly normal metabolic rate and thus require slightly more calories (11-12 calories) per pound. This individual would then accidentally put himself in a slight caloric deficit and lose weight.

These two methods should be more than enough for most people. But, perhaps you want to expand your options and learn a third method.

#3) Trial & Error
If, for some reason, you’re still not satisfied with the outcome of the above-mentioned methods and want to figure out your maintenance calories on your own, you can do so by doing the following:

  • Weigh yourself first thing in the morning after you use the bathroom and before you eat anything. Weigh yourself naked so that you eliminate the weight of clothes. Record that exact weight.
  • Do the same thing for the next 7 days.
  • Eat a specific number of calories for those 7 days and keep your activity level the same.
  • After 7 days, take your weights (there will be fluctuations, don’t worry), add them up and divide them by 7 to get your average weight.
  • Compare your average weight to the weight you recorded on the first day. Are they the same? If so, congratulations, you have found your maintenance calories.
  • If your weight increases, then you must’ve been eating a caloric surplus. Thus, decrease your caloric intake by 100-200 calories per day and repeat the same experiment to see the outcome.
  • If your weight decreases, then you must’ve been eating a caloric deficit. Thus, increase your caloric intake by 100-200 calories per day and repeat the experiment until you figure out how many calories you need per day to maintain your weight.

Now, you don’t need to do this experiment. Instead, you can just use any of the first two methods and those will give you a very close estimate to your real daily caloric requirements.

Keep in mind that it’s impossible to pinpoint exactly how many calories you need per day due to various factors including stress levels, medical conditions and normal physiological fluctuations. So, don’t get too worked up on being 100% accurate. Estimates will be more than enough.

I also don’t like relying on trial and error method because in my opinion it wastes time that could be better spent making progress. During those 7-14 days where you are trying to figure out how much to eat to maintain your weight, you could be losing fat, building muscle or both!

For now, just calculate your daily caloric requirements and keep that number because we will use it throughout this guide.

Depending on your goal, click on any of the articles below to proceed to the next step.

How many calories should I eat to lose weight? (weight, not fat. Remember?)
How many calories should I eat to lose fat? (we just want to lose FAT not muscle or water. Remember?)
Weight loss plateaus and how to work your way around them
How many calories should I eat to gain muscle/weight? (different, but have things in common. Remember?)
How many calories should I eat to MAINTAIN my weight? (maintain weight only or maintain weight and improve athletic performance.)
How many calories should I eat to recomp? (build muscle AND lose fat simultaneously)



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