TDEE Explained by Nutritionist

How to Calculate TDEE Accurately for Your Body & Activity

By: Jeremy Fox, CNC, CPT, BSEngPublished: May 3, 2024

Understanding your total daily energy expenditure (TDEE) is crucial for creating a healthy and effective nutrition plan. Once you determine how many calories you burn each day, you will know precisely how much to eat to lose weight or gain muscle.

However, relying on generic TDEE calculators can lead to inaccurate results, either overestimating or underestimating your daily calorie needs. As a nutrition coach, I am here to guide you on how to calculate your TDEE accurately so you can optimize your diet and achieve better results.

TDEE Calculator Blog Cover

What Is Total Daily Energy Expenditure?

Total daily energy expenditure (TDEE) is the amount of calories you burn daily. The main components of TDEE are basal metabolic rate (BMR), non-exercise activity thermogenesis (NEAT), and deliberate exercise.

Your BMR is the number of calories your body burns at rest, and it is mainly dictated by your lean body mass. NEAT is a fancy term for normal daily activities like standing and walking, while EAT is your physical activity level in actual workouts.

Some TDEE purists also include the thermic effect of food (TEF), which is the energy required to break down and digest food. However, TEF has a relatively small impact unless you make significant changes to your diet.

Components of TDEE

Why TDEE Matters

Understanding the total number of calories you burn is essential to create energy balance. When your calorie intake matches your TDEE, you will maintain your current weight, also known as your maintenance calories.

Furthermore, your TDEE can be considered the starting point for weight loss or weight gain. Eating fewer calories than you burn is called a calorie deficit, and it is crucial to lose weight. Conversely, eating more calories than you burn can help you build muscle mass.

If you’re not reaching your fitness goals, you probably need to reevaluate your calorie intake. The first step is finding your actual TDEE.

TDEE Calorie Deficit

How to Calculate TDEE

Several methods, including fitness trackers and online calculators, can be used to determine the number of calories you burn on a daily basis.

Using Fitness Trackers

​Wearable fitness trackers can be the most accurate way to find your total calories burned. Devices such as watches, rings, and chest straps measure your heart rate and calculate how much energy you burn throughout the day.

If used properly, these measurements provide a reasonably good approximation of your TDEE. However, this tech can be pretty expensive and only measures your energy expenditure while you wear it.

For this reason, TDEE calculators are a more accessible alternative.

TDEE Calorie Deficit

This is my average TDEE as measured by an Oura ring.

Using Calculators

If you search for TDEE calculators online, you will find several websites that offer similar services. These calculators require you to input your personal information, and they provide you with an estimate of the number of calories you burn in a day.

You may also receive recommendations for how much you should eat based on your fitness goal. However, the formula used can significantly influence the results you receive.

So, I will guide you through calculating TDEE to help you estimate your calorie needs more accurately.

TDEE Calculators Explained

I have been using Excel to create TDEE calculators since 2010 for myself and my clients. I have also developed a spreadsheet using the same formulas as the top websites to demonstrate how they function.

You can either watch my 6-minute YouTube video, where I explain how TDEE calculators operate, or continue reading below.

Mifflin-St Jeor Equation

The Harris-Benedict equation, updated by Mifflin-St Jeor in the 1990s, is the most commonly used TDEE formula. It calculates your BMR using your gender, body weight, height, and age.

An activity level multiplier is then applied to determine your TDEE. Activity multipliers are based on the number of days you exercise each week and vary between calculators.

For instance, if you have a sedentary lifestyle, your TDEE would only be about 20% more than your BMR (1.2x), while an extremely high activity level would result in a TDEE that is almost double (1.9x).

The downside of this equation is that it doesn’t consider body composition. This means the calculation is like body mass index (BMI) in that it ignores how much muscle or fat you have.

Table 1. Activity Level Definitions and Multipliers

Activity Level Definition Multiplier
Sedentary Little or no exercise & desk job 1.2
Low Light exercise 1-3 days per week 1.375
Moderate Medium exercise 3-5 days per week 1.55
High Hard exercise 6-7 days per week 1.725
Extreme Twice daily exercise & physical job 1.9

Katch-McArdle Equation

Most TDEE calculators also have an option for the Katch McArdle equation, which uses your weight and body fat percentage to calculate BMR. Then, the same activity factor is applied to determine TDEE.

If you are of average build (24% body fat for men or 33% for women), TDEE comes out almost identical to the Mifflin-St Jeor equation. However, the two formulas diverge if you have above or below-average body fat.

Therefore, the Katch McArdle equation is typically better if you know your body composition. However, both equations still be inaccurate.

Comparing TDEE Results

As an example, consider the average 30-year-old male, who is 5’9″ tall and weighs about 200 pounds with 24% body fat.

Using the Mifflin-St Jeor equation, his BMR would be 1,858 calories. If he has a moderate activity level, the multiplier would be 1.55, and his TDEE would be 2,879 calories.

By comparison, his BMR would be 1,859 calories, using the Katch McArdle equation. And his TDEE would be 2,887 calories, almost identical to the M-SJ number.

TDEE Calculator Comparison

Both TDEE formulas provide similar results for average body composition.

However, let’s say the man in our previous example was out of shape and had 34% body fat. At a given weight, he has less lean mass and a lower BMR, so his TDEE is almost 300 calories lower.

So, if he were using the M-SJ equation, he’d overestimate his calorie needs by 12% and probably wouldn’t lose any weight.

TDEE Calculator Body Composition Difference

Mifflin-St Jeor typically overestimates TDEE for overweight people.

On the flip side, if our guy had a below-average body fat percentage, say, 14%, his lean mass, BMR, and TDEE would be higher. So, if he were using the M-SJ to try to build muscle, he probably wouldn’t be eating enough and wouldn’t progress much in the gym.

TDEE Calculator Differences Explained

Mifflin-St Jeor typically underestimates TDEE for relatively lean people.

Problems With TDEE Formulas

Traditional calculators use sophisticated algebra to calculate BMR. However, they rely on a basic multiplier to find TDEE, which is a less accurate approach.

Additionally, research indicates that 27% of metabolic variation is unaccounted for even when lean mass is included in the calculation1.

To address these issues, I have created a new predictive equation that considers individual variations in metabolism and more accurately defines your activity level.

TDEE Variation Explained

Source: Wikipedia

Most Accurate TDEE Calculator

I created a TDEE calculator for Nutritioneering using the Katch McArdle equation as a base. To adjust your BMR, I applied a body type multiplier.

If you’re unfamiliar with body types, they are classifications related to genetic variation. Ectomorphs generally have a faster metabolism, while endomorphs tend to have a slower one.

However, it is essential to note that body types are not just three categories used to label people. Instead, they are more like a spectrum, and it is possible to have a mix of body types.

For instance, a sprinter would likely be a mix of ectomorph and mesomorph (ecto-meso). On the other hand, a shot-putter might be a mix of endomorph and mesomorph (endo-meso).

TDEE Body Type

Next, I divided activity level into daily movements based on your job and how much walking you do, while exercise calories are calculated separately. Calories burned during exercise are directly related to your average heart rate.

For example, strength training and cardio workouts are medium-intensity (120-150 bpm). Lower-intensity activities like yoga or cardio have a heart rate of less than 120 beats per minute, while high-intensity interval training (HIIT) can reach over 150 beats per minute.

TDEE Exercise Intensity

The exciting part is that I can also calculate TDEE for a rest day and determine an average TDEE based on the number of days per week you exercise. This allows for implementing precise calorie and carb cycling.

To illustrate, I entered my numbers into all three calculators and compared the results to my average TDEE, measured by my Apple Watch and Oura ring. My average TDEE is lower than the standard equations predicted, but my equation was within 2%.

The main reason the standard TDEE calculators are inaccurate is the single activity multiplier isn’t flexible enough. Additionally, conventional calculators can be off by +/-15% because they don’t have an input for metabolic variation.

On the other hand, the Nutritioneering TDEE calculator uses your actual workout intensity and duration and your activity outside the gym. Plus, it has a built-in metabolism factor to improve accuracy.

Therefore, the best TDEE calculator is the one that adjusts to your unique body composition, body type, and workout routine.

Click Here to Try My Accurate Online TDEE Calculator for Free

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Finding Your Calorie Intake

Once you know your TDEE, the next step is determining your daily caloric intake based on your fitness goal.

For Fat Loss

When you aim to burn fat, you must create a caloric deficit by eating less calories than you burn. However, you don’t want to restrict calories too much, or you will experience muscle loss and a decreased metabolic rate.

Therefore, the ideal calorie deficit is the smallest one that results in weight loss. For the average person, that amounts to eating 200-300 calories less than your TDEE.

If you don’t see results or if your progress slows down, you can gradually increase your calorie deficit by eating less or increasing the total amount of energy you expend.

My Calorie Deficit Calculator Tells You How Much To Eat For Weight Loss

TDEE Calorie Deficit Transformation

For Muscle Gain

When your goal is to gain muscle, you must create a caloric surplus by eating more calories than you burn. However, in this case, overshooting could result in excess fat gain.

For lean bulking, a calorie surplus of 200-300 calories is sufficient to maximize muscle growth without gaining fat. Again, you can incrementally increase your calorie target as needed to continue making gains.

I Created The Most Accurate Bulking Calorie Calculator

TDEE Calorie Surplus

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